JP2010197903A - Plasma display and method for driving plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress power consumption of a data electrode driving IC and a power circuit below a rated value while maintaining image display quality. <P>SOLUTION: A plasma display includes: a power consumption calculation part 50 of each data electrode driving IC; a maximum value calculation part 52 which calculate the maximum value of each power consumption; a sum calculation part 51 which calculates the sum of each power consumption; a first comparison part 53 which compares the sum of the power consumption with a first threshold; a second comparison part 56 which compares the maximum of the power consumption with a second threshold and a third threshold; threshold changing parts 54, 55 which change values of the second and third thresholds on the basis of comparison results of the first comparison part 53; and an LPF intensity control part 60 which multiplies an image signal by predetermined LPF intensity to change LPF intensity. The predetermined LPF intensity is changed on the basis of comparison results of the first comparison part 53 and the second comparison part 56. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma display device and a plasma display panel driving method 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 at 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 for driving the panel, a subfield method is generally used (see, for example, Patent Document 1). In the subfield method, one field period is divided into a plurality of subfields, and gradation display is performed by causing each discharge cell to emit light or not emit light in each subfield. Each subfield has an initialization period, an address period, and a sustain period.

  In the initialization period, an initialization waveform is applied to each scan electrode, and an initialization discharge is generated in each discharge cell. Thereby, wall charges necessary for the subsequent address operation are formed in each discharge cell.

  In the address period, a scan pulse is sequentially applied to the scan electrodes (hereinafter, this operation is also referred to as “scan”), and an address pulse corresponding to an image signal to be displayed is applied to the data electrodes (hereinafter, these operations are performed). Are collectively referred to as “writing”). Thereby, an address discharge is selectively generated between the scan electrode and the data electrode, and a wall charge is selectively formed.

  In the subsequent sustain period, a predetermined number of sustain pulses corresponding to the luminance to be displayed are alternately applied to the display electrode pair composed of the scan electrode and the sustain electrode. Thereby, a discharge is selectively caused in the discharge cell in which the wall charge is formed by the address discharge, and the discharge cell is caused to emit light. Thereby, an image is displayed.

  The plurality of scan electrodes are driven by a scan electrode drive circuit, the plurality of sustain electrodes are driven by a sustain electrode drive circuit, and the plurality of data electrodes are driven by a data electrode drive circuit.

  On the other hand, in recent years, power consumption in a panel tends to increase with an increase in screen size and brightness. Further, in a panel with a large screen and high definition, the load at the time of driving the panel increases, so that the discharge tends to become unstable. In order to generate the discharge stably, the drive voltage applied to the electrode may be increased, but this contributes to further increasing the power consumption. Further, if the drive voltage is increased or the power consumption is increased to exceed the rated values of the components constituting the drive circuit, the circuit may malfunction.

  For example, the data electrode driving circuit performs an operation of applying an address pulse to the data electrode to generate an address discharge in the discharge cell, but the power consumption at the time of addressing is an IC (for example, data electrode driving) constituting the data electrode driving circuit. If the rated value of the IC is exceeded, the IC malfunctions and an address failure occurs such that an address discharge does not occur in a discharge cell that should generate an address discharge, or an address discharge occurs in a discharge cell that should not generate an address discharge. There is a fear.

  Therefore, in order to suppress power consumption during writing, a technique for limiting the number of gradation values used when displaying an image has been proposed (for example, see Patent Document 2).

Also disclosed is a method for predicting the power consumption of the data electrode driving circuit based on the image signal to be displayed and limiting the display gradation when the predicted value exceeds a set value in order to suppress the power consumption during writing. (For example, see Patent Document 3).
JP 2006-18298 A JP 2004-21166 A JP 2000-66638 A

  In general, a plurality of data electrode driving ICs are used in a plasma display device, and all data electrode driving is performed from one power supply circuit so that the power supply voltage supplied to each data electrode driving IC does not vary. Many are configured to supply power to the IC.

  Therefore, even if the power consumption of all the data electrode driving ICs is less than the rated value, if the power consumption of each data electrode driving IC is large, the power consumption in the power supply circuit that supplies power to the data electrode driving IC is reduced. The rated value of the power circuit may be exceeded.

  On the other hand, even if the power consumption in one data electrode driving IC exceeds the rated value, if the power consumption in the other data electrode driving IC is small, the power consumption in the power supply circuit that supplies power to the data electrode driving IC is The rated value of the power circuit is not exceeded.

  In addition, the power consumption in the power supply circuit and the individual power consumption of the data electrode driving IC are greatly different. Therefore, in a configuration that controls the overall power consumption while monitoring the individual power consumption of the data electrode driving IC, the control performed to reduce the power consumption tends to be overcorrected, while maintaining the image display quality, It has been very difficult to keep the power consumption in the data electrode drive IC and the power supply circuit that supplies power to the data electrode drive IC within their rated values.

  The present invention has been made in view of these problems. By adjusting the image signal in accordance with the total power consumption and the maximum value of each power consumption in the data electrode driving IC, the data is maintained while maintaining the image display quality. It is an object of the present invention to provide a plasma display device and a panel driving method capable of suppressing the power consumption of an electrode driving IC and a power supply circuit below a rated value.

  The plasma display device of the present invention is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and is provided with a plurality of discharge cells having data electrodes. A plurality of data electrode driving ICs for driving the data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the data pulse to the data electrode, and an input image signal in a subfield of the discharge cell. An image signal processing circuit for converting the image data to indicate image emission / non-emission for each image, the image signal processing circuit calculating a sum of power consumption of all the data electrode driving ICs, and calculating the sum A first comparison unit for comparing the total power consumption calculated in the unit with a first threshold value; An LPF intensity control unit that performs low-pass filter (hereinafter referred to as LPF) processing with a predetermined intensity on the input image signal, and an LPF intensity change unit that changes the intensity of the LPF process of the LPF intensity control unit, The LPF intensity changing unit outputs a signal for changing the predetermined LPF intensity value to the LPF intensity control unit based on the comparison result in the first comparing unit.

  The plasma display device of the present invention is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and is provided with a plurality of discharge cells having data electrodes. A plurality of data electrode driving ICs for driving the plurality of data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the data pulse to the data electrode, and a subfield in the discharge cell. An image signal processing circuit that converts image data indicating light emission / non-light emission for each of the image signal processing circuits, the power consumption calculation unit that calculates the power consumption of each of the data electrode driving ICs, and the power consumption The maximum value of each power consumption of the data electrode driving IC calculated in the calculation unit is calculated. A maximum value calculation unit that performs a LPF process on the input image signal with a predetermined intensity, a second comparison unit that compares a maximum value of power consumption calculated by the maximum value calculation unit and a second threshold value And an LPF intensity changing unit for changing the intensity of the LPF processing of the LPF intensity control unit, the LPF intensity changing unit based on the comparison result in the second comparing unit. A signal for changing a value of a predetermined LPF intensity is output to the LPF intensity control unit.

  The plasma display device of the present invention is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and is provided with a plurality of discharge cells having data electrodes. A panel, a plurality of data electrode driving ICs for driving the data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the data pulse to the data electrode, and an input image signal in the discharge cell An image signal processing circuit for converting into image data indicating light emission / non-light emission for each field, the image signal processing circuit calculating power consumption of each of the data electrode driving ICs, and the power consumption Maximum value of each power consumption of the data electrode driving IC calculated in the power calculation unit A maximum value calculation unit to be calculated; a total calculation unit for calculating the sum of each power consumption of the data electrode driving IC calculated by the power consumption calculation unit; and a total sum of the power consumption calculated by the total calculation unit A first comparison unit that compares the threshold value of 1, a maximum value of power consumption calculated by the maximum value calculation unit, a second threshold value, and a value that is smaller than the second threshold value A threshold value for changing a value of the second threshold value and the third threshold value based on a comparison result in the second comparison unit comparing the third threshold value and the first comparison unit; A value changing unit, an LPF intensity control unit that changes the intensity of a predetermined LPF in the image signal, and a first LPF intensity or a second LPF intensity are selected based on a comparison result in the first comparison unit An LPF intensity selection unit, An LPF intensity changing unit that changes the predetermined LPF intensity based on the output of the PF intensity selecting unit and the comparison result of the second comparing unit, and the LPF intensity changing unit is output from the LPF intensity selecting unit A signal for changing a value of the predetermined LPF intensity based on a comparison result in the second comparison unit to either the first LPF intensity or the second LPF intensity is output to the LPF intensity control unit. It is characterized by this.

  The method for driving a plasma display panel according to the present invention includes an initialization period, an address period, and a sustain period for one field of an image signal input to a plasma display panel having a plurality of discharge cells having data electrodes, scan electrodes, and sustain electrodes. In a method for driving a plasma display panel that is driven by a subfield method for displaying gradation in a plurality of subfields, the image signal is subjected to low-pass filter processing (hereinafter referred to as LPF processing) with a predetermined intensity; Converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell, and power consumption of a plurality of data electrode driving ICs for applying an address pulse to the data electrode based on the image data Calculating a sum, a value of the power consumption sum and a first Comparing a threshold, it is characterized in further comprising the step of changing the predetermined intensity based on the comparison result.

  The plasma display panel driving method according to the present invention includes an initialization period, an address period, and a sustain period for one field of an image signal input to a plasma display panel including a plurality of discharge cells having data electrodes, scan electrodes, and sustain electrodes. Performing a low-pass filter process (hereinafter referred to as an LPF process) with a predetermined intensity on the image signal in a method for driving a plasma display panel that is driven by a sub-field method for displaying gray scales divided into a plurality of sub-fields. A step of converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell; and each of a plurality of data electrode driving ICs for applying an address pulse to the data electrode based on the image data Calculating a maximum value of power consumption of Comparing a maximum value and a second threshold force, it is characterized in further comprising the step of changing the predetermined intensity based on the comparison result.

  The plasma display panel driving method according to the present invention includes an initialization period, an address period, and a sustain period for one field of an image signal input to a plasma display panel including a plurality of discharge cells having data electrodes, scan electrodes, and sustain electrodes. Performing a low-pass filter process (hereinafter referred to as an LPF process) with a predetermined intensity on the image signal in a method for driving a plasma display panel that is driven by a sub-field method for displaying gray scales divided into a plurality of sub-fields. Converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell; and consumption of a plurality of data electrode driving ICs for applying an address pulse to the data electrode based on the image data Calculating a power sum, a value of the power consumption sum and a first A first comparison step for comparing the threshold value of the plurality of data electrode driving ICs for applying a write pulse to the data electrode based on the image data, and calculating a maximum value of power consumption of each of the plurality of data electrode driving ICs; , A second comparison step of comparing the maximum value of the power consumption with a second threshold value and a third threshold value smaller than the second threshold value, the first comparison step, and And a step of changing the predetermined intensity based on the comparison result of the second comparison step.

  A plasma display device of the present invention is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and includes a panel having a plurality of discharge cells having data electrodes, A plurality of data electrode driving ICs for driving a plurality of data electrodes, a data electrode driving circuit that generates an address pulse during an address period and applies the data pulse to the data electrode, and light emission / non-light emission for each subfield in the discharge cell. An image signal processing circuit for converting the image data into image data, and the image signal processing circuit calculates a sum of power consumption of all the data electrode driving ICs and a sum of power consumption calculated by the sum calculation unit and A first comparison unit that compares the threshold value of 1 and a power consumption control unit, and is based on the comparison result of the first comparison unit. And changes a control amount of the power consumption in the power control unit.

  Alternatively, the image signal processing circuit includes a power consumption calculation unit that calculates power consumption of each of the data electrode driving ICs, and a maximum value among the power consumptions of the data electrode driving ICs calculated by the power consumption calculation unit. A maximum value calculation unit that calculates the power consumption, a second comparison unit that compares the maximum value of power consumption calculated by the maximum value calculation unit and the second threshold value, and a power consumption control unit, The control amount of power consumption in the power consumption control unit is changed based on the comparison result of one comparison unit.

  Alternatively, the image signal processing circuit calculates a power consumption calculation unit that calculates each power consumption of the data electrode driving IC, and calculates a maximum value among the power consumptions of the data electrode driving IC calculated by the power consumption calculation unit. A maximum value calculating unit, a sum calculating unit for calculating the sum of each power consumption of the data electrode driving IC calculated by the power consumption calculating unit, a sum of the power consumption calculated by the sum calculating unit and a first threshold A first comparison unit that compares values, a maximum value of power consumption calculated by the maximum value calculation unit, a second threshold value, and a third threshold value that is smaller than the second threshold value A second comparison unit that compares the second threshold value, a threshold value changing unit that changes the values of the second threshold value and the third threshold value based on the comparison result in the first comparison unit, and a power consumption control unit The comparison result of the first comparison unit And changes a control amount of power consumption in the power consumption control unit based on the comparison result of the preliminary second comparison unit.

  As a result, the power consumption can be controlled according to the maximum value of each power consumption of the data electrode driving IC and the sum of the power consumptions, so that the consumption of the data electrode driving IC and the power supply circuit is maintained while maintaining the image display quality. It becomes possible to suppress electric power below each rated value.

  In this plasma display device, as the power consumption control unit, the image signal processing circuit changes an LPF intensity control unit that performs LPF processing on the image signal with a predetermined intensity, and changes the LPF processing intensity of the LPF intensity control unit. And an LPF intensity changing unit that adds or subtracts the LPF intensity from the LPF intensity based on the comparison result in the first comparison unit to obtain a new predetermined LPF intensity. And changing the value of the predetermined LPF intensity.

  Alternatively, as the power consumption control unit, the image signal processing circuit includes an LPF intensity control unit that performs LPF processing on the image signal with a predetermined intensity, and an LPF intensity change unit that changes the intensity of the LPF process of the LPF intensity control unit. In the LPF intensity changing unit, the predetermined LPF intensity is obtained by adding or subtracting the LPF intensity to the LPF intensity based on the comparison result in the second comparison unit to obtain a new predetermined LPF intensity. The value of is changed.

  Alternatively, as the power consumption control unit, the LPF intensity control unit that changes the intensity of the predetermined LPF to the image signal, and the predetermined LPF intensity is changed based on the comparison result of the first comparison unit and the comparison result of the second comparison unit Select one of the first LPF intensity and the second LPF intensity based on the comparison result in the first comparison unit, the limiter that limits the predetermined LPF intensity to a predetermined upper limit value or less An LPF intensity selection unit that performs either of the first LPF intensity and the second LPF intensity output from the LPF intensity selection unit based on the comparison result in the second comparison unit. The value of the predetermined LPF intensity is changed by adding or subtracting the LPF intensity to or from the predetermined LPF intensity to obtain a new predetermined LPF intensity.

  As a result, the LPF intensity can be controlled according to the maximum value of each power consumption of the data electrode driving IC and the total power consumption, so that the power consumption of the data electrode driving IC and the power supply circuit can be rated while maintaining the image display quality. It becomes possible to keep it below the value.

  Further, in this plasma display device, the LPF intensity changing unit includes a first LPF intensity output from the LPF intensity selecting unit when the second comparing unit determines that the maximum value is equal to or greater than the second threshold value. Alternatively, either the second LPF intensity is added from the predetermined LPF intensity to obtain a new predetermined LPF intensity, and when the second comparison unit determines that the maximum value is less than the third threshold, the LPF One of the first LPF intensity and the second LPF intensity output from the intensity selecting unit is subtracted from the predetermined LPF intensity to obtain a new predetermined LPF intensity. As a result, the magnitude of the image signal can be accurately controlled according to the maximum value of each power consumption of the data electrode driving IC and the total power consumption, so that the data electrode driving IC and the data electrode driving IC can be maintained while maintaining the image display quality. It becomes possible to perform the control which suppresses the power consumption of the power supply circuit below the rated value, respectively, with higher accuracy.

  In this plasma display device, the LPF intensity changing unit is configured to output a predetermined LPF intensity when the second comparing unit determines that the maximum value is greater than or equal to the third threshold value and less than the second threshold value. It is good also as a structure which does not change.

  In this plasma display device, the LPF intensity changing unit is preferably configured to update a predetermined LPF intensity at a time interval that is an integral multiple of one field period. Thereby, it is possible to prevent the LPF intensity from changing in the middle of one field period, so that the image display quality can be further improved.

  In the panel driving method of the present invention, a panel having a plurality of discharge cells having data electrodes is provided with a plurality of subfields having an initialization period, an address period, and a sustain period in one field period, and a plurality of data A panel driving method in which an address pulse is generated in an address period using an electrode driving IC and applied to a data electrode to drive the panel, and is calculated by a sum calculating unit and a sum calculating unit for calculating the total power consumption of all the data electrode driving ICs. A first comparison unit that compares the sum of the consumed power and the first threshold value, and a power consumption control unit, and based on a comparison result of the first comparison unit, The control amount is changed.

  Alternatively, a power consumption calculation unit that calculates the power consumption of each of the data electrode drive ICs, and a maximum value calculation that calculates the maximum value among the power consumptions of the data electrode drive ICs calculated by the power consumption calculation unit A first comparison unit, a second comparison unit that compares the maximum value of power consumption calculated by the maximum value calculation unit with a second threshold value, and a power consumption control unit. The power consumption control amount in the power consumption control unit is changed based on the result.

  Alternatively, the power consumption of each of the data electrode driving ICs is calculated, the maximum value of the calculated power consumptions of the data electrode driving IC and the sum of the power consumptions are respectively calculated, and the calculated sum and the first A first threshold value, and a second threshold value and a third threshold value smaller than the second threshold value based on a comparison result between the sum and the first threshold value. The calculated maximum value is compared with the second threshold value and the third threshold value, the comparison result between the sum and the first threshold value, and the maximum value and the second threshold value are compared. The control amount of power consumption is changed based on a comparison result between the threshold value and the third threshold value.

  Accordingly, the power consumption depends on the total power consumption of all the data electrode drive ICs, the maximum value of each power consumption of the data electrode drive IC, or the maximum value of each power consumption of the data electrode drive IC and the sum of each power consumption. Therefore, it is possible to suppress the power consumption of the data electrode driving IC and the power supply circuit below the rated values while maintaining the image display quality.

  The panel driving method of the present invention is a panel driving method for controlling power consumption by multiplying an image signal by a predetermined LPF intensity, the comparison result between the sum and the first threshold value, and Based on the comparison result between the maximum value and the second threshold value and the third threshold value, the predetermined LPF intensity is changed within a predetermined upper limit value range, and the total is compared with the first threshold value. Based on the result, either the first LPF intensity or the second LPF intensity is selected, and either the selected first LPF intensity or the second LPF intensity is set to the maximum value and the second threshold value. Based on the comparison result with the third threshold value, the predetermined LPF intensity value is changed by adding or subtracting to the predetermined LPF intensity to obtain a new predetermined LPF intensity, and the power consumption control amount is changed. It is characterized by doing. As a result, the LPF intensity can be controlled according to the maximum value of each power consumption of the data electrode driving IC and the total power consumption, so that the power consumption of the data electrode driving IC and the power supply circuit can be rated while maintaining the image display quality. It becomes possible to keep it below the value.

  In the panel driving method according to the present invention, when the maximum value is determined to be equal to or greater than the second threshold value, either the selected first LPF intensity or the second LPF intensity is set to a predetermined LPF intensity. To obtain a new predetermined LPF intensity, and when it is determined that the maximum value is less than the third threshold value, either the selected first LPF intensity or the second LPF intensity is set to the predetermined LPF intensity. The intensity is subtracted to obtain a new predetermined LPF intensity. As a result, the LPF intensity can be accurately controlled in accordance with the maximum value of each power consumption of the data electrode driving IC and the total power consumption, so that the data electrode driving IC and the power supply circuit can be maintained while maintaining the image display quality. It becomes possible to perform the control which suppresses power consumption below a rated value more accurately.

  In the panel driving method of the present invention, the predetermined LPF intensity does not have to be changed when it is determined that the maximum value is not less than the third threshold value and less than the second threshold value.

  In the panel driving method of the present invention, it is desirable to update the predetermined LPF intensity at a time interval that is an integral multiple of one field period. As a result, it is possible to prevent the LPF intensity from changing in the middle of one field period, so that the image display quality can be further improved. The LPF intensity control method includes a method for controlling the LPF intensity for each color, a method for controlling the screen vertical direction and the screen horizontal direction, a method for increasing the LPF intensity at the screen edge, and a direction from the screen center to the screen edge. Gradually increasing the LPF intensity, gradually increasing the LPF intensity concentrically from the center of the screen toward the edge of the screen, and evenly and horizontally in the vertical direction from the center of the screen. There is a method of gradually increasing the LPF intensity toward the part, and control is performed so that image quality deterioration is not as conspicuous as possible.

  The means for solving the problem may be a method of controlling the number of LPF control lines instead of the LPF intensity. For example, the number of LPF control lines is increased instead of increasing the LPF intensity, and the number of LPF control lines is decreased instead of decreasing the LPF intensity. As a method for controlling the number of LPF control lines, a method for controlling the number of LPF control lines for each color, a method for controlling the number of LPF control lines for the screen vertical direction and the screen horizontal direction, and a method for increasing the number of LPF control lines at the screen edge. A method of gradually increasing the number of LPF control lines from the screen center to the screen edge, gradually increasing the number of LPF control lines from the screen center to the screen edge uniformly in the vertical direction and horizontally. There is a method of gradually increasing the number of LPF control lines at equal intervals in the vertical direction or the horizontal direction, and the control is performed so that the image quality deterioration is not conspicuous as much as possible.

  According to the present invention, the power consumption of the data electrode driving IC and the power supply circuit is maintained while maintaining the image display quality by adjusting the image signal in accordance with the sum of the power consumption and the maximum value of each power consumption in the data electrode driving IC. It is possible to provide a plasma display device and a panel driving method that can keep the value below the rated value.

  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 according to an embodiment of the present invention. On the front plate 21 made of glass, a plurality of display electrode pairs 24 each including a scanning electrode 22 and a sustain electrode 23 are formed. A dielectric layer 25 is formed so as to cover the scan electrode 22 and the sustain electrode 23, and a protective layer 26 is formed on the dielectric layer 25.

  The protective layer 26 has been used as a panel material in order to lower the discharge start voltage in the discharge cell, and has a large secondary electron emission coefficient and durability when neon (Ne) and xenon (Xe) gas is sealed. It is formed from a material mainly composed of MgO having excellent properties.

  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 24 and the data electrode 32 intersect with 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. A mixed gas of neon and xenon is sealed as a discharge gas in the internal discharge space. In the present embodiment, a discharge gas having a xenon partial pressure of about 10% is used in order to improve luminous efficiency. 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. Further, the mixing ratio of the discharge gas is not limited to the above-described numerical values, and may be other mixing ratios.

  FIG. 2 is an electrode array diagram of panel 10 according to the embodiment 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) arranged in the row direction. The m data electrodes D1 to Dm (data electrodes 32 in FIG. 1) extending 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. A region where m × n discharge cells are formed becomes a display region of the panel 10.

  Next, a driving voltage waveform for driving the panel 10 and an outline of the operation will be described with reference to FIG. Note that the plasma display device in this embodiment is a subfield method, that is, one field period is divided into a plurality of subfields on the time axis, luminance weights are set for each subfield, and each discharge is performed for each subfield. It is assumed that gradation display is performed by controlling light emission / non-light emission of the cell.

  In this subfield method, for example, one field is composed of ten subfields (first SF, second SF,..., Tenth SF), and each subfield is, for example, (1, 2, 3, 6, 11). , 18, 30, 44, 60, 80). Further, among the plurality of subfields, an all-cell initializing operation for generating an initializing discharge in all discharge cells is performed in the initializing period of one subfield, and the immediately preceding period is set in the initializing period of the other subfield. By performing selective initializing operation that selectively generates initializing discharge for discharge cells that have undergone sustain discharge in the subfield, it is possible to reduce light emission not related to gradation display as much as possible and improve the contrast ratio. is there.

  In the present embodiment, the all-cell initialization operation is performed in the initialization period of the first SF, and the selective initialization operation is performed in the initialization period of the second SF to the tenth SF. As a result, the light emission not related to the image display is only the light emission due to the discharge of the all-cell initialization operation in the first SF, and the black luminance, which is the luminance of the black display area that does not generate the sustain discharge, is weak in the all-cell initialization operation. Only the emission of light makes it possible to display an image with high contrast. In the sustain period of each subfield, the number of sustain pulses obtained by multiplying the luminance weight of each subfield by a predetermined luminance magnification is applied to each display electrode pair 24.

  In the present invention, the number of subfields and the luminance weight of each subfield are not limited to the above values as in the present embodiment, and the subfield configuration is switched based on an image signal or the like. It may be.

  FIG. 3 is a drive voltage waveform diagram applied to each electrode of panel 10 in one embodiment of the present invention.

  In FIG. 3, scan electrode SC1 that performs scanning first in the address period, scan electrode SCn that scans last in the address period (for example, scan electrode SC1080), sustain electrode SU1 to sustain electrode SUn, and data electrode D1 ~ Shows drive waveforms of the data electrode Dm.

  FIG. 3 also shows drive voltage waveforms of two subfields, that is, a first subfield (first SF) of a subfield that performs an all-cell initialization operation (referred to as an “all-cell initialization subfield”), A second subfield (second SF) of a subfield (referred to as “selective initialization subfield”) for performing a selective initialization operation is shown. The drive voltage waveform in the other subfields is substantially the same as the drive voltage waveform of the second SF except that the number of sustain pulses in the sustain period is different. In addition, scan electrode SCi, sustain electrode SUi, and data electrode Dk in the following represent electrodes selected from each electrode based on image data.

  First, the first SF, which is an all-cell initialization subfield, will be described.

  In the first half of the initializing period of the first SF, 0 (V) is applied to each of the data electrode D1 to the data electrode Dm, the sustain electrode SU1 to the sustain electrode SUn, and the scan electrode SC1 to the scan electrode SCn starts from 0 (V). A voltage Vi1 that is equal to or lower than the discharge start voltage is applied, and a ramp waveform voltage (hereinafter referred to as “up-ramp waveform”) that gradually rises from voltage Vi1 toward voltage Vi2 that exceeds the discharge start voltage with respect to sustain electrode SU1 through sustain electrode SUn. L1 is applied.

  While the rising ramp waveform L1 rises, between scan electrode SC1 through scan electrode SCn and sustain electrode SU1 through sustain electrode SUn, and between scan electrode SC1 through scan electrode SCn and data electrode D1 through data electrode Dm. Each weak initializing discharge occurs continuously. Negative wall voltage is accumulated above scan electrode SC1 through scan electrode SCn, and positive wall voltage is accumulated above data electrode D1 through data electrode Dm and sustain electrode SU1 through sustain electrode SUn. 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 latter half of the initialization period, positive voltage Ve1 is applied to sustain electrode SU1 through sustain electrode SUn, 0 (V) is applied to data electrode D1 through data electrode Dm, and scan electrode SC1 through scan electrode SCn. Down-slope waveform voltage (hereinafter referred to as “down-ramp waveform”) that gradually falls from voltage Vi3 that is equal to or lower than the discharge start voltage to negative voltage Vi4 that exceeds the discharge start voltage with respect to sustain electrode SU1 through sustain electrode SUn. Apply L2.

  During this time, weak initialization discharges occur between scan electrode SC1 through scan electrode SCn and sustain electrode SU1 through sustain electrode SUn, and between scan electrode SC1 through scan electrode SCn and data electrode D1 through data electrode Dm, respectively. . Then, the negative wall voltage above scan electrode SC1 through scan electrode SCn and the positive wall voltage above sustain electrode SU1 through sustain electrode SUn are weakened, and the positive wall voltage above data electrode D1 through data electrode Dm is used for the write operation. It is adjusted to a suitable value. Thus, the all-cell initializing operation for performing the initializing discharge on all the discharge cells is completed.

  In the subsequent address period, a scan pulse voltage is sequentially applied to scan electrode SC1 through scan electrode SCn, and data electrode Dk (k = 1) corresponding to a discharge cell to emit light is applied to data electrode D1 through data electrode Dm. To m), a positive address pulse voltage Vd is applied to selectively generate an address discharge in each discharge cell.

  In this address period, voltage Ve2 is first applied to sustain electrode SU1 through sustain electrode SUn, and voltage Vc (Vc = Va + Vscn) is applied to scan electrode SC1 through scan electrode SCn.

  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 write pulse voltage Vd is applied to. 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 in externally applied voltage (Vd−Va). It becomes the sum and exceeds the discharge start voltage. As a result, a discharge is generated between data electrode Dk and scan electrode SC1. Since voltage Ve2 is applied to sustain electrode SU1 through sustain electrode SUn, the voltage difference between sustain electrode SU1 and scan electrode SC1 is the difference between the externally applied voltages (Ve2-Va) and sustain electrode SU1. The difference between the upper wall voltage and the wall voltage on the scan electrode SC1 is added.

  At this time, by setting the voltage Ve2 to a voltage value that is slightly lower than the discharge start voltage, the sustain electrode SU1 and the scan electrode SC1 are not easily discharged but are likely to be discharged. Can do. Thereby, the discharge generated between data electrode Dk and scan electrode SC1 can be triggered to generate a discharge between sustain electrode SU1 and scan electrode SC1 in the region intersecting with data electrode Dk. Thus, an address discharge occurs in the discharge cell to emit light, a positive wall voltage is accumulated on scan electrode SC1, a negative wall voltage is accumulated on sustain electrode SU1, and a negative wall voltage is also accumulated on data electrode Dk. Accumulated.

  In this way, an address operation is performed in which an address discharge is caused in the discharge cell to emit light in the first row and wall voltage is accumulated on each electrode. On the other hand, the voltage at the intersection of data electrode D1 to data electrode Dm to which scan pulse SC1 is not applied with address pulse voltage Vd does not exceed the discharge start voltage, so that address discharge does not occur. The above address operation is sequentially performed until the discharge cell in the nth row, and the address period ends.

  In the subsequent sustain period, sustain pulses of the number obtained by multiplying the luminance weight by a predetermined luminance magnification are 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 this sustain period, first, positive sustain pulse voltage Vs is applied to scan electrode SC1 through scan electrode SCn, and a ground potential serving as a base potential, that is, 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 difference between the wall voltage on scan electrode SCi and the wall voltage on sustain electrode SUi. Exceeding 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) as the base potential is applied to scan electrode SC1 through scan electrode SCn, and sustain pulse 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. Thereafter, similarly, sustain pulses of the number obtained by multiplying the luminance weight by the luminance magnification are alternately applied to scan electrode SC1 through scan electrode SCn and sustain electrode SU1 through sustain electrode SUn, thereby giving a potential difference between the electrodes of display electrode pair 24. As a result, the sustain discharge is continuously performed in the discharge cells that have caused the address discharge in the address period.

  At the end of the sustain period, after the sustain electrode SU1 to the sustain electrode SUn are returned to 0 (V), the ramp waveform voltage increases from 0 (V), which is the base potential, toward the voltage Vers exceeding the discharge start voltage. L3 (hereinafter referred to as “erasing ramp waveform”) is applied to scan electrode SC1 through scan electrode SCn. Then, a weak discharge (hereinafter referred to as “erase discharge”) occurs between sustain electrode SUi and scan electrode SCi of the discharge cell in which the sustain discharge has occurred. The charged particles generated by the erasing discharge are accumulated as wall charges on the sustain electrode SUi and the scan electrode SCi so as to alleviate the voltage difference between the sustain electrode SUi and the scan electrode SCi.

  Thus, the wall voltage on the scan electrode SCi and the sustain electrode SUi remains the difference between the voltage applied to the scan electrode SCi and the discharge start voltage, that is, (voltage Vers−discharge) while leaving the positive wall charge on the data electrode Dk. It is weakened to the extent of the starting voltage. Thereafter, scan electrode SC1 to scan electrode SCn are returned to 0 (V), and the sustain operation in the sustain period is completed.

  In the initialization period of the second SF, a drive voltage waveform in which the first half of the initialization period of the first SF is omitted is applied to each electrode. That is, voltage Ve1 is applied to sustain electrode SU1 through sustain electrode SUn, and 0 (V) is applied to data electrode D1 through data electrode Dm, respectively, and voltage that is equal to or less than the discharge start voltage (for example, 0) is applied to scan electrode SC1 through scan electrode SCn. (V)) is applied to the ramp-down waveform L4 that gently falls toward the negative voltage Vi4. As a result, a weak initializing discharge is generated in the discharge cell that has caused the sustain discharge in the sustain period of the immediately preceding subfield (first SF in FIG. 3), and the wall voltage on the scan electrode SCi and the sustain electrode SUi is weakened. The wall voltage above the data electrode Dk (k = 1 to m) is also adjusted to a value suitable for the write operation.

  On the other hand, discharge cells in which no sustain discharge has occurred in the previous subfield are not discharged, and the wall charge state at the end of the initialization period of the previous subfield is maintained as it is. As described above, the initializing operation in the second SF is a selective initializing operation in which the initializing discharge is performed on the discharge cells in which the sustain operation has been performed in the sustain period of the immediately preceding subfield.

  In the address period of the second SF, a drive waveform similar to that in the address period of the first SF is applied to scan electrode SC1 through scan electrode SCn, sustain electrode SU1 through sustain electrode SUn, and data electrode D1 through data electrode Dm.

  In the sustain period of the second SF, similarly to the sustain period of the first SF, a predetermined number of sustain pulses are alternately applied to scan electrode SC1 through scan electrode SCn and sustain electrode SU1 through sustain electrode SUn. As a result, a sustain discharge is generated in the discharge cells that have generated the address discharge in the address period.

  In the subfields after the third SF, scan electrode SC1 to scan electrode SCn, sustain electrode SU1 to sustain electrode SUn, and data electrode D1 to data electrode Dm differ from the second SF except for the number of sustain pulses in the sustain period. A similar drive waveform is applied.

  The above is the outline of the driving voltage waveform applied to each electrode of the panel 10.

  Next, the configuration of the plasma display device in the present embodiment will be described. FIG. 4 is a circuit block diagram of plasma display device 1 according to one embodiment of the present invention. The plasma display apparatus 1 includes a panel 10, 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 power supply circuit that supplies necessary power to each circuit block. (Not shown).

  The image signal processing circuit 41 converts the input image signal sig into image data indicating light emission / non-light emission for each subfield according to the number of pixels of the panel 10.

  The data electrode drive circuit 42 converts the image data for each subfield output from the image signal processing circuit 41 into address pulses corresponding to the data electrodes D1 to Dm, and each data electrode D1 based on the timing signal. Apply to the data electrode Dm. In the data electrode drive circuit 42, a large number of data electrodes must be driven independently based on the image data. Therefore, in the present embodiment, the data electrode drive circuit 42 can drive a plurality of data electrodes. A plurality of dedicated ICs (hereinafter referred to as “data electrode driving ICs”) 47 are provided. Hereinafter, in this embodiment, the number m of data electrodes is “5760” (1920 × 3 (R, G, B) = 5760), and the number of outputs of one data electrode driving IC is “360”. The data electrode drive circuit 42 will be described as including 16 data electrode drive ICs 47 (data electrode drive IC 47 (1) to data electrode drive IC 47 (16)). However, these numerical values are merely examples, and the present invention is not limited to the numerical values described above in terms of the number of data electrodes, the number of outputs of the data electrode driving IC, and the like.

  The timing generation circuit 45 generates various timing signals for controlling the operation of each circuit block based on outputs from the horizontal synchronization signal H and the vertical synchronization signal V, and each circuit block (image signal processing circuit 41, data electrode drive). Circuit 42, scan electrode drive circuit 43, and sustain electrode drive circuit 44).

  Scan electrode drive circuit 43 includes an initialization waveform generation circuit (not shown) for generating an initialization waveform to be applied to scan electrode SC1 through scan electrode SCn in the initialization period, and includes a plurality of scan ICs, and scans in the write period. Scan pulse generating circuit (not shown) for generating scan pulses to be applied to electrode SC1 through scan electrode SCn, and sustain pulse generating circuit for generating sustain pulses to be applied to scan electrode SC1 through scan electrode SCn in the sustain period (Not shown). Then, each scan electrode SC1 to scan electrode SCn is driven based on the timing signal.

  Sustain electrode drive circuit 44 includes a sustain pulse generation circuit and a circuit (not shown) for generating voltage Ve1 and voltage Ve2, and drives sustain electrode SU1 through sustain electrode SUn based on a timing signal.

  Next, details of the image signal processing circuit 41 will be described. FIG. 5 is a circuit block diagram of the image signal processing circuit 41 according to the embodiment of the present invention. FIG. 5 shows circuit blocks related to power consumption control in this embodiment, and other circuit blocks are omitted.

  The image signal processing circuit 41 includes a power consumption calculation unit 50, a total calculation unit 51, a maximum value calculation unit 52, a first comparison unit 53, a second comparison unit 56, a threshold value changing unit 54, It has a threshold value changing unit 55, an LPF intensity control unit 60 as a power consumption control unit, an LPF intensity selection unit 57 and an LPF intensity changing unit 58, and a limiter 59.

  The power consumption calculation unit 50 calculates the power consumption in the data electrode driving IC 47 based on the image data for each subfield generated from the image signal in the image signal processing circuit 41. The calculation of power consumption in the data electrode driving IC 47 can be performed as follows, for example.

  The power consumption in the data electrode driving IC 47 is such that a discharge cell that generates an address discharge (hereinafter referred to as “lighting cell”) and a discharge cell that does not generate an address discharge (hereinafter referred to as “non-lighting cell”) are adjacent. The number increases as the number of matches increases, and the number decreases as the number of adjacent lighting cells or non-lighting cells increases. This is because the data electrode driving IC 47 generates a write pulse by switching a plurality of switching elements included therein, and the number of switching of switching elements increases as the number of lit cells and non-lighted cells increases. Conversely, the larger the number of adjacent lighting cells or non-lighting cells is, the more the switching frequency of the switching element is reduced.

  The power consumption calculation unit 50 can use this to calculate the power consumption in the data electrode drive IC 47. For example, a lighted cell is set to “1”, a non-lighted cell is set to “0”, an exclusive OR operation is performed between adjacent discharge cells, and the results are cumulatively added. Thereby, the number of locations where the lighted cell and the non-lighted cell are adjacent can be counted. If the relationship between the cumulative addition value obtained in this way and the power consumption in the data electrode driving IC 47 is examined in advance and the data is provided to the power consumption calculation unit 50, the cumulative addition value described above can be calculated. Thus, power consumption can be calculated. However, the present invention is not limited to this method for calculating power consumption, and may be configured to calculate power consumption by other methods.

  In the present embodiment, the data electrode driving circuit 42 includes 16 data electrode driving ICs 47, that is, the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16). Therefore, the power consumption calculation unit 50 can also calculate the power consumption of each data electrode drive IC 47, so that the 16 power consumption calculation units 50, that is, the data electrode drive IC 47 (1) to the data electrode drive IC 47 (16) can be calculated. Assume that the power consumption calculation unit 50 (1) to the power consumption calculation unit 50 (16) that calculate the power consumption corresponding to each of them are provided.

  The maximum value calculator 52 calculates the maximum value among the power consumptions calculated by the power consumption calculator 50 (1) to the power consumption calculator 50 (16). Moreover, the sum total calculation part 51 calculates the sum total of each power consumption calculated in the power consumption calculation part 50 (1)-power consumption calculation part 50 (16).

  The first comparison unit 53 compares the sum calculated by the sum calculation unit 51 with a preset first threshold value. For example, when the sum is equal to or greater than the first threshold value, “1” is set. When the sum is less than the first threshold, “0” is output. In the present embodiment, the value of the first threshold value is set in consideration of the rated value of power consumption in the power supply circuit that supplies power to the data electrode driving IC 47. For example, when the sum calculated by the sum calculator 51 is equal to or greater than the first threshold, it can be determined that the power consumption of the power supply circuit that supplies power to the data electrode driving IC 47 is likely to exceed the rated value. Set to a value like this.

  The second comparison unit 56 calculates the maximum value calculated by the maximum value calculation unit 52, the second threshold value set in advance, and the third threshold value smaller than the second threshold value. Compare. For example, when the maximum value is equal to or greater than the second threshold value, “11” is set. When the maximum value is less than the third threshold value, “00” is set. When it is less than the threshold value of 2, “01” is output.

  In the present embodiment, it is assumed that the second threshold value is changed in threshold change unit 54 based on the comparison result in first comparison unit 53. For example, when “1” is output from the first comparison unit 53, “TH2p” is output as the second threshold value, and when “0” is output from the first comparison unit 53, the second threshold value is output. “TH2d” is output as the threshold value.

  Similarly, the value of the third threshold value is also changed in the threshold value changing unit 55 based on the comparison result in the first comparing unit 53. For example, when “1” is output from the first comparator 53, “TH3p” is output as the third threshold value, and when “0” is output from the first comparator 53, the third threshold is output. “TH3d” is output as the threshold value.

  In the present embodiment, the value of the second threshold value is set in consideration of the rated value of power consumption in the data electrode driving IC 47. For example, when the maximum value calculated by the maximum value calculation unit 52 is equal to or greater than the second threshold value, the data electrode driving IC 47 is set to a value that can determine that the power consumption is likely to exceed the rated value. To do. In addition, when the power consumption in the power supply circuit that supplies power to the data electrode driving IC 47 is large, the output of “11” from the second comparison unit 56 as soon as possible is the protection of the power supply circuit and the data electrode driving IC 47. It is desirable from the viewpoint of protection. Therefore, “TH2p” that is selected as the second threshold value when “1” is output from the first comparison unit 53 is the second threshold value that is selected when “0” is output from the first comparison unit 53. It is desirable to set a value smaller than “TH2d” selected as the threshold value of 2.

  Note that the second threshold value and the third threshold value may be independent of the first threshold value.

  A low-pass filter strength control unit (hereinafter referred to as LPF strength control unit) 60 multiplies the image signal by a predetermined low-pass filter strength (hereinafter referred to as LPF strength) to change the magnitude of the LPF strength. In the present embodiment, the power consumption is controlled by changing the LPF intensity in the LPF intensity control unit 60 in this way. For example, if the LPF intensity value multiplied by the image signal is increased, the display image becomes blurred and the power consumption is reduced. Conversely, if the value of the LPF intensity multiplied by the image signal is reduced, the display image becomes clear and the power consumption increases.

  The low-pass filter strength changing unit (hereinafter referred to as the LPF strength changing unit) 58 is either the first LPF strength output from the LPF strength selecting unit 57 or the second LPF strength having a value smaller than the first LPF strength. These are added or subtracted from the predetermined LPF intensity used in the LPF intensity control unit 60 based on the comparison result in the second comparison unit 56 to obtain a new predetermined LPF intensity. In this way, the LPF intensity control unit 60 changes the predetermined LPF intensity value to be multiplied by the image signal. The LPF intensity selector 57 outputs the first LPF intensity when “1” is output from the first comparator 53, and the second when “0” is output from the first comparator 53. The LPF intensity is output. The first LPF intensity and the second LPF intensity correspond to “change values of intensity”.

  Note that the predetermined LPF intensity output from the LPF intensity changing unit 58 is limited to an LPF intensity upper limit value which is a predetermined upper limit value in the limiter 59 so that the LPF intensity is not excessively increased in the LPF intensity control unit 60. Are input to the LPF intensity control unit 60. Further, in order to prevent the LPF intensity from changing in the middle of one field period, the LPF intensity changing unit 58 updates the predetermined LPF intensity at a cycle of an integral multiple of one field period (for example, three field periods). To do.

  Next, details of the operation when changing the value of the predetermined LPF intensity based on the comparison result in the first comparison unit 53 and the comparison result in the second comparison unit 56 will be described. FIG. 6 is a schematic diagram for explaining the operation of changing the value of the predetermined LPF intensity in one embodiment of the present invention.

  As shown in FIG. 6, in the present embodiment, when the comparison result in the first comparison unit 53 is “0” and the comparison result in the second comparison unit 56 is “11”, that is, the data electrode The sum of the power consumptions of drive IC 47 (1) to data electrode drive IC 47 (16) is less than the first threshold value, and any one of data electrode drive IC 47 (1) to data electrode drive IC 47 (16) When the power consumption exceeds the second threshold value, the power supply circuit that supplies power to the data electrode driving IC 47 is not so heavily loaded, but the data electrode driving IC 47 (1) to the data electrode driving IC 47 ( 16), it can be determined that the power consumption may exceed the rated value of the data electrode driving IC 47.

  Therefore, in such a case, the second LPF intensity having a value smaller than the first LPF intensity is added from the predetermined LPF intensity to obtain a new predetermined LPF intensity, and the LPF intensity multiplied by the image signal is increased. In any of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16), the power consumption is prevented from exceeding the rated value of the data electrode driving IC 47. As a result, when the power consumption in any one of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16) increases, the LPF intensity is increased and the power consumption in the data electrode driving IC 47 is promptly rated. It can be:

  Further, when the comparison result in the first comparison unit 53 is “1” and the comparison result in the second comparison unit 56 is “11”, that is, the data electrode drive IC 47 (1) to the data electrode drive IC 47 (16). ) Is greater than or equal to the first threshold value, and any one of the data electrode drive IC 47 (1) to the data electrode drive IC 47 (16) is greater than or equal to the second threshold value. When this occurs, a large load is applied to the power supply circuit that supplies power to the data electrode driving IC 47, and power consumption is rated for the data electrode driving IC 47 in any of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16). It can be determined that the value may be exceeded.

  Therefore, in such a case, the first LPF intensity having a value larger than the second LPF intensity is added from the predetermined LPF intensity to obtain a new predetermined LPF intensity, and the LPF intensity multiplied by the image signal is further increased. The load applied to the power supply circuit that supplies power to the data electrode driving IC 47 is reduced, and the power consumption of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16) exceeds the rated value of the data electrode driving IC 47. Do not. As a result, when the load on the power supply circuit that supplies power to the data electrode drive IC 47 becomes large, the LPF strength is further increased and the load on the power supply circuit that supplies power to the data electrode drive IC 47 is quickly reduced. Can do.

  When the comparison result in the first comparison unit 53 is “0” and the comparison result in the second comparison unit 56 is “00”, the power supply circuit that supplies power to the data electrode driving IC 47 has a very large load. It can be determined that the power consumption of any of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16) is lower than the rated value of the data electrode driving IC 47. Therefore, in such a case, the second LPF intensity is subtracted from the predetermined LPF intensity to obtain a new predetermined LPF intensity, and the LPF intensity multiplied by the image signal is weakened to make the display image clear. As a result, the design of the display image changes, and when the load in the power supply circuit that supplies power to the data electrode driving IC 47 and the power consumption in the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16) are reduced, the display is displayed. The image can be quickly returned to the original LPF intensity and displayed.

  When the comparison result in the first comparison unit 53 is “0” and the comparison result in the second comparison unit 56 is “01”, the power supply circuit that supplies power to the data electrode driving IC 47 has a very large load. Further, it can be determined that the power consumption does not exceed the rated value of the data electrode driving IC 47 in any of the data electrode driving IC 47 (1) to the data electrode driving IC 47 (16). Therefore, in such a case, the predetermined LPF intensity value is not changed, and fluctuations in the display image are suppressed.

  A state in which the comparison result in the first comparison unit 53 is “1” and the comparison result in the second comparison unit 56 is “00” or “01” is also considered as a combination. However, when a large load is applied to the power supply circuit that supplies power to the data electrode driving IC 47, it is desirable to reduce the load on the power supply circuit as quickly as possible. Therefore, when the comparison result in the first comparison unit 53 is “1”, it is desirable to set the value of TH2p so that the comparison result in the second comparison unit 56 is also “11”. However, in the present invention, the value of TH2p is not limited, the comparison result in the first comparison unit 53 is “1”, and the comparison result in the second comparison unit 56 is “00” or “01”. In such a case, the LPF intensity may be changed as shown in FIG. 6, for example.

  With this configuration, it is possible to suppress the power consumption in the data electrode drive IC 47 and the power supply circuit that supplies power to the data electrode drive IC 47 within the respective rated values while maintaining the image display quality on the panel 10 as much as possible. Become.

  For example, even if the power consumption in all the data electrode driving ICs 47 is less than the rated value, if the power consumption in all the data electrode driving ICs 47 is large, the power consumption in the power supply circuit that supplies power to the data electrode driving IC 47 is The rated value of the power supply circuit may be exceeded. Since the power consumption in the power supply circuit is larger than the individual power consumption of the data electrode driving IC 47, in such a case, it is desirable to reduce the power consumption as quickly as possible.

  On the other hand, even if the power consumption in one data electrode driving IC 47 exceeds the rated value, if the power consumption in the other data electrode driving IC 47 is small, the power consumption in the power supply circuit that supplies power to the data electrode driving IC 47 is The rated value of the power circuit is not exceeded. In such a case, it is desirable to reduce the power consumption so that the power consumption in the data electrode driving IC 47 falls below the rated value while suppressing the change in the display image as much as possible.

  According to the present embodiment, with the above-described configuration, the power consumption in the power supply circuit that supplies power to the data electrode driving IC 47 and the data electrode driving IC 47 is maintained while maintaining the image display quality in the panel 10. It is possible to keep it within the rated value.

  As described above, in the present embodiment, the power consumption calculator 50 (1) to the power consumption calculator 50 (16) that calculate the power consumption of each of the data electrode driver IC 47 (1) to the data electrode driver IC 47 (16). ), A maximum value calculation unit 52 for calculating the maximum value among the power consumptions calculated in the power consumption calculation unit 50 (1) to the power consumption calculation unit 50 (16), and the power consumption calculation unit 50 (1). The power consumption calculation unit 50 (16) compares the total power calculation unit 51 that calculates the total power consumption calculated by the power consumption calculation unit 50 (16) with the first threshold value. The first comparison unit 53 and a second comparison unit 56 that compares the maximum value of power consumption calculated by the maximum value calculation unit 52 with the second threshold value and the third threshold value are provided. Configure and threshold The second and third threshold values are changed based on the comparison result in the first comparison unit 53 in the further change unit 54 and the threshold change unit 55, and the comparison result in the first comparison unit 53. Further, the LPF intensity control unit 60 changes the magnitude of a predetermined LPF intensity to be multiplied by the image signal based on the comparison result in the second comparison unit 56, thereby maintaining the image display quality on the panel 10 and maintaining the data electrode. It becomes possible to suppress the power consumption in the power supply circuit that supplies power to the drive IC 47 and the data electrode drive IC 47 within the respective rated values.

  The LPF intensity control method includes a method for controlling the LPF intensity for each color, a method for controlling the screen vertical direction and the screen horizontal direction, a method for increasing the LPF intensity at the screen edge, and a direction from the screen center to the screen edge. 9, a method of gradually increasing the LPF intensity, a method of gradually increasing the LPF intensity from the center of the screen toward the edge of the screen concentrically as shown in FIG. 9, and a center of the screen as shown in FIG. There is a method of gradually increasing the LPF intensity toward the edge of the screen evenly in the vertical direction and uniformly in the horizontal direction, and control is performed so that image quality deterioration is not as conspicuous as possible.

  In the present embodiment, the first threshold value is set in consideration of the power consumption rating value in the power supply circuit that supplies power to the data electrode driving IC 47, and the power consumption rating value in the data electrode driving IC 47 is set. However, for example, a configuration may be adopted in which each threshold value is set in consideration of a rated value related to heat.

  In the present embodiment, the configuration in which the power consumption is controlled by controlling the LPF intensity in the LPF intensity control unit 60 has been described. However, a method for controlling the number of LPF control lines instead of the LPF intensity as shown in FIG. The power consumption may be controlled by the above. For example, the number of LPF control lines is increased instead of increasing the LPF intensity, and the number of LPF control lines is decreased instead of decreasing the LPF intensity. FIG. 8 is a schematic diagram for explaining the operation of changing the value of the predetermined number of LPF control lines in one embodiment of the present invention.

  As a method for controlling the number of LPF control lines, a method for controlling the number of LPF control lines for each color, a method for controlling the number of LPF control lines for the screen vertical direction and the screen horizontal direction, and a method for increasing the number of LPF control lines at the screen edge. , A method of gradually increasing the number of LPF control lines from the screen center to the screen edge, as shown in FIG. 11, from the screen center toward the screen edge uniformly in the vertical direction and even in the horizontal direction. The method of gradually increasing the number of LPF control lines, as shown in FIG. 12, first set the predetermined number of vertical LPF control lines 66, and when further increasing the number of control lines, set the predetermined number of vertical LPF control lines 67. A method of gradually increasing the number of LPF control lines at regular intervals in the vertical direction, first set a predetermined number of horizontal LPF control lines 68 as shown in FIG. Furthermore, when the number of control lines is increased, there is a method in which the predetermined number of horizontal LPF control lines 69 is added, and the number of LPF control lines is gradually increased at equal intervals not only in the vertical direction but also in the horizontal direction. Control so that is not conspicuous.

  In the embodiment of the present invention, the scan electrode and the scan electrode are adjacent to each other, and the sustain electrode and the sustain electrode are adjacent to each other. , Scan electrode, sustain electrode, sustain electrode, scan electrode, scan electrode,... ”Is also effective in a panel having an electrode structure (referred to as“ ABBA electrode structure ”).

  It should be noted that the specific numerical values shown in the embodiment of the present invention are set based on the characteristics of a panel of 50 inches and 1080 pairs of display electrodes, and are merely examples of the embodiment. Absent. The present invention is not limited to these numerical values, and is desirably set optimally according to the characteristics of the panel, the specifications of the plasma display device, and the like. Each of these numerical values is allowed to vary within a range where the above-described effect can be obtained.

  In the embodiment of the present invention, the configuration in which erase ramp waveform L3 is applied to scan electrode SC1 through scan electrode SCn has been described. However, the erase ramp waveform L3 is applied to sustain electrode SU1 through sustain electrode SUn. You can also. Alternatively, an erasing discharge may be generated not by the erasing ramp waveform L3 but by a so-called narrow erasing pulse.

  According to the present invention, the power consumption of the data electrode driving IC and the power supply circuit is rated while maintaining the image display quality by adjusting the image signal according to the total sum of the power consumption and the maximum value of each power consumption in the data electrode driving IC. It becomes possible to suppress to below the value, and it is useful as a driving method of a plasma display device and a panel.

1 is an exploded perspective view showing a structure of a plasma display panel according to an embodiment of the present invention. The figure which shows the electrode arrangement of the panel The figure which shows the drive voltage waveform impressed to each electrode of the panel The circuit block diagram of the plasma display apparatus in one embodiment of the present invention FIG. 3 is a circuit block diagram of a portion having a function of reducing data power by controlling the LPF intensity in the image signal processing circuit of the present invention. The figure which shows the outline for demonstrating the operation | movement which changes the value of the predetermined LPF intensity | strength in one embodiment of this invention. 1 is a circuit block diagram of an image signal processing circuit according to an embodiment for reducing data power by controlling the number of LPF control lines according to the present invention. The figure which shows the outline for demonstrating the operation | movement which changes the value of the predetermined number of LPF control lines in one embodiment of this invention. The figure for demonstrating the method to make LPF intensity | strength of the LPF intensity | strength of this invention gradually toward the edge part of a screen concentrically from the screen center part. The figure for demonstrating the method to gradually increase the LPF intensity | strength of the LPF intensity | strength of this invention toward a screen edge part from the screen center part equally to a vertical direction and a horizontal direction equally. The figure for demonstrating the method to gradually increase the number of LPF control lines toward the screen edge part from the screen center part equally to a horizontal direction and the horizontal direction of this invention. The figure for demonstrating the method to gradually increase the number of LPF control lines of the present invention at equal intervals in the vertical direction. The figure for demonstrating the method to gradually increase the number of LPF control lines in the horizontal direction at equal intervals of the LPF control line of this invention.

1 Plasma display device 10 Panel (Plasma display panel)
21 Front plate (made of glass) 22 Scan electrode 23 Sustain electrode 24 Display electrode pair 25, 33 Dielectric layer 26 Protective layer 31 Back plate 32 Data electrode 34 Partition 35 Phosphor layer 41 Image signal processing circuit 42 Data electrode drive circuit 43 Scan electrode drive circuit 44 Sustain electrode drive circuit 45 Timing generation circuit 47 Data electrode drive IC
DESCRIPTION OF SYMBOLS 50 Power consumption calculation part 51 Sum total calculation part 52 Maximum value calculation part 53 1st comparison part 54,55 Threshold value change part 56 2nd comparison part 57 LPF intensity | strength selection part 58 LPF intensity change part 59 Limiter 60 LPF intensity control Unit 61 LPF control line number selection unit 62 LPF control line number change unit 63 LPF control line number control unit 64 Direction to increase LPF intensity 65 LPF control line number increase direction 66, 67 Vertical LPF control line number 68, 69 Horizontal LPF Number of control lines

Claims (9)

A plasma display panel that is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and includes a plurality of discharge cells having data electrodes;
A plurality of data electrode driving ICs for driving the data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the address pulse to the data electrode;
An image signal processing circuit that converts an input image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell;
The image signal processing circuit includes:
A sum total calculation unit for calculating the total power consumption of all the data electrode driving ICs;
A first comparison unit that compares the total power consumption calculated by the total calculation unit with a first threshold;
An LPF intensity control unit that performs a low-pass filter (hereinafter referred to as LPF) process on the input image signal with a predetermined intensity;
An LPF intensity changing unit for changing the intensity of the LPF process of the LPF intensity control unit,
The LPF intensity changing unit outputs a signal for changing a value of the predetermined LPF intensity to the LPF intensity control unit based on a comparison result in the first comparing unit. A plasma display panel that is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and includes a plurality of discharge cells having data electrodes;
A plurality of data electrode driving ICs for driving the plurality of data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the address pulse to the data electrode;
An image signal processing circuit that converts an input image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell,
A power consumption calculation unit for calculating the power consumption of each of the data electrode driving ICs;
A maximum value calculation unit that calculates a maximum value of the power consumption of each of the data electrode driving ICs calculated by the power consumption calculation unit;
A second comparison unit that compares a maximum value of power consumption calculated by the maximum value calculation unit with a second threshold value;
An LPF intensity controller that performs LPF processing on the input image signal at a predetermined intensity;
An LPF intensity changing unit for changing the intensity of the LPF process of the LPF intensity control unit,
The LPF intensity changing unit outputs a signal for changing a value of the predetermined LPF intensity to the LPF intensity control unit based on a comparison result in the second comparing unit. A plasma display panel that is driven by a subfield method in which a plurality of subfields having an initialization period, an address period, and a sustain period are provided in one field period, and includes a plurality of discharge cells having data electrodes;
A plurality of data electrode driving ICs for driving the data electrodes, a data electrode driving circuit for generating an address pulse during the address period and applying the address pulse to the data electrode;
An image signal processing circuit that converts an input image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell,
A power consumption calculation unit for calculating the power consumption of each of the data electrode driving ICs;
A maximum value calculation unit that calculates a maximum value of the power consumption of each of the data electrode driving ICs calculated by the power consumption calculation unit;
A total calculation unit that calculates the total of the power consumption of each of the data electrode driving ICs calculated by the power consumption calculation unit;
A first comparison unit that compares the total power consumption calculated by the total calculation unit with a first threshold;
A second comparison unit that compares the maximum value of power consumption calculated by the maximum value calculation unit with a second threshold value and a third threshold value that is smaller than the second threshold value; ,
A threshold value changing unit that changes values of the second threshold value and the third threshold value based on a comparison result in the first comparing unit;
An LPF intensity controller that changes the intensity of a predetermined LPF to the image signal;
An LPF intensity selection unit that selects either the first LPF intensity or the second LPF intensity based on the comparison result in the first comparison unit;
An LPF intensity changing unit that changes the predetermined LPF intensity based on an output of the LPF intensity selecting unit and a comparison result of the second comparing unit;
The LPF intensity changing unit is configured to use either the first LPF intensity or the second LPF intensity output from the LPF intensity selecting unit based on a comparison result in the second comparing unit. A plasma display device characterized by outputting a signal for changing the value of the value to the LPF intensity controller. The LPF intensity changing unit is
When the second comparison unit determines that the maximum value is greater than or equal to the second threshold value, either the first LPF strength or the second LPF strength output from the LPF strength selection unit Is added from the predetermined LPF intensity to obtain a new predetermined LPF intensity,
In the second comparison unit, when the maximum value is determined to be less than the third threshold value, either the first LPF intensity or the second LPF intensity output from the LPF intensity selection unit 4. The plasma display apparatus according to claim 3, wherein the predetermined LPF intensity is subtracted from the predetermined LPF intensity to obtain a new predetermined LPF intensity. A field of an image signal input to a plasma display panel having a plurality of discharge cells each having a data electrode, a scan electrode, and a sustain electrode is divided into a plurality of subfields having an initialization period, an address period, and a sustain period. In a driving method of a plasma display panel driven by a subfield method of displaying,
Performing low pass filter processing (hereinafter referred to as LPF processing) on the image signal with a predetermined intensity;
Converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell;
Calculating a power consumption sum of a plurality of data electrode driving ICs that apply an address pulse to the data electrode based on the image data;
Comparing the value of the total power consumption with a first threshold;
And a step of changing the predetermined intensity based on the comparison result. A field of an image signal input to a plasma display panel having a plurality of discharge cells each having a data electrode, a scan electrode, and a sustain electrode is divided into a plurality of subfields having an initialization period, an address period, and a sustain period. In a driving method of a plasma display panel driven by a subfield method of displaying,
Performing low pass filter processing (hereinafter referred to as LPF processing) on the image signal with a predetermined intensity;
Converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell;
Calculating a maximum value of power consumption of each of a plurality of data electrode driving ICs that applies a write pulse to the data electrode based on the image data;
Comparing the maximum value of the power consumption with a second threshold value;
And a step of changing the predetermined intensity based on the comparison result. A field of an image signal input to a plasma display panel having a plurality of discharge cells each having a data electrode, a scan electrode, and a sustain electrode is divided into a plurality of subfields having an initialization period, an address period, and a sustain period. In a driving method of a plasma display panel driven by a subfield method of displaying,
Performing low pass filter processing (hereinafter referred to as LPF processing) on the image signal with a predetermined intensity;
Converting the image signal into image data indicating light emission / non-light emission for each subfield in the discharge cell;
Calculating a power consumption sum of a plurality of data electrode driving ICs that apply an address pulse to the data electrode based on the image data;
A first comparison step of comparing a value of the total power consumption with a first threshold;
Calculating a maximum value of power consumption of each of a plurality of data electrode driving ICs that applies a write pulse to the data electrode based on the image data;
A second comparison step of comparing the maximum value of the power consumption with a second threshold value and a third threshold value smaller than the second threshold value;
A plasma display panel driving method comprising: changing the predetermined intensity based on a comparison result of the first comparison step and the second comparison step. 8. The method of driving a plasma display panel according to claim 7, further comprising a step of changing the second threshold value and the third threshold value based on a comparison result of the first comparison step. Selecting and outputting an intensity change value based on the comparison result of the first comparison step;
8. The driving of a plasma display panel according to claim 7, further comprising a step of changing the value of the predetermined intensity by adding or subtracting the change value to or from the predetermined intensity based on a comparison result of the second comparison step. Method.

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