JP3656645B2 - Display device - Google Patents

Description

  The present invention relates to a technique for driving a display device such as a display device such as a personal computer or a workstation, a flat wall-mounted television, a plasma display panel for displaying advertisements or information.

  For example, in a conventional AC type plasma display with an address display separation system, an address discharge that defines a pixel (cell) that emits light is simultaneously applied to address electrodes by performing one horizontal line (R, G, and B colors). The voltage was also constant regardless of the color. Prior to the address discharge, the voltage applied to the address electrode in the reset period for initializing the charge state of each cell was constant regardless of R, G, and B.

  However, the appropriate voltage for the address discharge differs depending on the type of the light emitting medium such as a phosphor provided in the address electrode section or the discharge characteristics of each address electrode including the difference due to the difference in the light emitting medium. If the voltage applied to the electrodes is constant, there are disadvantages that the voltage range for performing stable display is narrowed and the types of light emitting media such as phosphors that can be selected are limited.

  It is an object of the present invention to provide a display technique that improves the drawbacks of the prior art, eliminates discharge errors of address electrodes, and provides a display image with stable image quality.

  In the present invention, the voltage applied to the address electrode is set to a value corresponding to the discharge characteristics of each address electrode including the phosphor (light emitting medium), so that the selection of the phosphor type is not restricted, and the phosphor The address discharge is surely performed at an appropriate voltage corresponding to the type of the image so as to obtain a stable image.

  In the present invention, since individual address electrodes can be discharged in a wide control voltage range, reliable address discharge can be easily performed, and a discharge error can be eliminated and a high-quality image can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The embodiment of the present invention will be described with reference to FIGS.

  FIG. 2 is an exploded perspective view showing a part of the structure of the plasma display panel of the present invention. A transparent X electrode 22 and a transparent Y electrode 23 are provided on the lower surface of the front glass substrate 21. Further, an X bus electrode 24 and a Y bus electrode 25 are laminated on each electrode. Further, a dielectric 26 and a protective layer 27 such as MgO are provided on the lower surface. On the other hand, an address A electrode 29 is provided on the upper surface of the rear glass substrate 28 in a direction perpendicular to the X electrode 22 and the Y electrode 23 of the front glass substrate 21. A dielectric 30 covers the address A electrode 29, and a partition wall 31 is provided in parallel to the address A electrode 29. Further, a phosphor 32 is applied to the dielectric 30 on the partition wall 31 and the address A electrode 29 as a light emitting medium (light emitting medium).

  FIG. 3 is a cross-sectional view of three cells of the plasma display panel as seen from the direction of arrow A in FIG. The address A electrode 29 is located in the middle of the partition wall 31, and one address A electrode 29 is provided for each phosphor color. In this example, three types of phosphors are applied in the order of R, G, and B. A space 33 between the front glass substrate 21 and the back glass substrate 28 is filled with a discharge gas such as Ne or Xe.

  FIG. 4 is a view from the direction of arrow B in FIG. 2, and is a cross-sectional view of three cells of the plasma display panel. The boundary of one cell is a position indicated by a dotted line, and X electrodes 22 and Y electrodes 23 are alternately arranged. In the AC type plasma display panel, positive and negative charges are separately collected on the dielectric in the vicinity of the X electrode 22 and the Y electrode 23, and an electric field for discharging is formed using this charge.

  FIG. 5 is a schematic diagram showing the wiring and circuit configuration of the X electrode 22, the Y electrode 23, and the address A electrode 29. The X drive circuit 34 generates a drive pulse to be applied to the X electrode 22. The Y drive circuit 35 is connected to each Y electrode 23 and generates a drive pulse to be applied to the Y electrode 23. The A driving circuit 36 is connected to each address A electrode 29 and generates a driving pulse to be applied to the address A electrode 29.

  FIG. 6 is a schematic diagram showing the wiring and circuit configuration of the address A electrode 29. In this embodiment, the phosphors are arranged in the order of R, G, and B from the left side of the figure. The address A electrodes 29 are alternately drawn in the vertical direction of the panel every other line, and are connected to the R address driver 37, the G address driver 38, and the B address driver 39 for each color of the phosphor. ing.

  FIG. 7 shows an example of measurement results of the discharge voltage at the Y electrode 23 and the address A electrode 29 in each phosphor. The composition of the phosphor used in this measurement is (Y, Gd) BO3: Eu, G is Zn2SiO4: Mn, and B is BaMgAl10O17: Eu, but this is only an example. Among these measured phosphors, the G phosphor has a higher discharge voltage than the other phosphors. However, some other G phosphors have a low discharge voltage. The same applies to R and B phosphors.

  FIG. 8 is a diagram showing a field configuration in the present invention. In the figure, 40 represents one field period, the horizontal axis represents time t (one field period), and the vertical axis represents cell row y. In this case, one field is divided into first to eighth subfields 41 to 48, and the first subfield 41 is assigned as the subfield with the smallest number of discharges, and the subfields are arranged in the order of the smallest number of discharges. The fields are arranged. Each subfield 41-48 has a reset period 41a-48a first. Subsequently, address periods 41b to 48b for defining cells to be displayed are provided. Further, there are sustain discharge periods 41c to 48c in which only cells in which charges are formed by address discharge are discharged. In the sustain discharge periods 43c to 48c, the number of discharges is assigned to each, and halftone display is performed by a combination of the number of discharges. Although the number of discharges and the order of subfields are arbitrary, there are also subfields in which discharge is repeated many times in succession.

  FIG. 1 is a time chart showing a part of a drive waveform of one subfield in the present embodiment. (A) is a part of the drive waveform applied to the X electrode 22, (b) is a part of the drive waveform applied to, for example, the first row (Y1) of the Y electrode 23, and (c) ), (D), (e) are applied to the electrodes (AR, AG, AB) of the address A electrode 29 corresponding to, for example, red (R), green (G), and blue (B) phosphors. Part of the driving waveform.

  For example, in one subfield 41, the waveform applied to the X electrode 22 includes a reset pulse 1 in the reset period 41a, an X scan pulse 2 in the address period 41b, and an X sustain discharge pulse 3 in the sustain discharge period 41c. At this time, the reset pulse 1 is set to a voltage higher than the discharge start voltage.

  Next, the waveform applied to, for example, the first row (Y1) of the Y electrode 23 includes a scan pulse 4 in the address period 41b, a first sustain discharge pulse 5 in the sustain discharge period 41c, and a Y sustain discharge pulse 6, respectively. .

  Next, the waveform applied to the electrode corresponding to, for example, the red phosphor of the address A electrode 29 is the address pulse (pulse for performing address discharge) 7 and the sustain discharge in the address period 41b corresponding to the cell to emit light. It consists of pulses 10 (hereinafter referred to as full-surface pulses) corresponding to pulses (pulses for performing sustain discharge). If there is no cell to emit light, there is no address pulse 7. Further, the address pulse 7 and the entire surface pulse 10 are set to substantially the same voltage Vr. The waveforms applied to the electrodes corresponding to the other phosphors, green (G) and blue (B) are the same as in the case of red, and the entire pulses corresponding to the address pulses 8 and 9 and the sustain discharge pulse in the address period 41b. 11 and 12, the address pulse 8 and the entire surface pulse 11, and the address pulse 9 and the entire surface pulse 12 are set to substantially the same voltages Vg and Vb, respectively. This voltage is set in the order of Vg, Vr, Vb from the highest corresponding to each discharge voltage, and the power supply voltage supplied to the address drivers 37, 38, 39 in the A drive circuit 36 is changed. Obviously, when the magnitude relationship of the discharge voltage differs depending on the phosphor type, the magnitude relationships of Vg, Vr, and Vb also differ.

  Next, the operation will be described. Address discharge occurs in the cells to which the address pulses 7, 8, and 9 are applied with respect to the scan pulse 4, and positive charged particles are formed on the dielectric 26 near the Y electrode 23 and on the dielectric 26 near the X electrode 22. Negative charged particles are accumulated in. Only in the cell in which the charged particles are accumulated, continuous discharge occurs in the subsequent first sustain discharge pulse 5, Y sustain discharge pulse 6, and X sustain discharge pulse 3. At this time, since the discharge voltage generated between the address electrode 29 and the Y electrode 23 differs depending on the type (color) of the phosphor, the address discharge is applied when an appropriate voltage is applied for each color according to the discharge voltage. Thus, a reliable operation can be obtained without causing a discharge in a cell that does not perform an address discharge.

  As described above, the discharge operation can be stabilized by changing the voltage applied to the address electrode 29 in accordance with the type of phosphor.

  Next, another embodiment will be described with reference to FIG. FIG. 9 is a time chart showing a part of the drive waveform of one subfield in the present embodiment. (A) is a part of the drive waveform applied to the X electrode 22, (b) is a part of the drive waveform applied to, for example, the first row (Y1) of the Y electrode 23, and (c). , (D), (e) are driving applied to the electrodes (AR, AG, AB) of the address A electrode 29 corresponding to phosphors of red (R), green (G), blue (B), for example. Part of the waveform. The same drive pulses as those in FIG. 1 are denoted by the same reference numerals as those in FIG. In FIG. 7, the waveform applied to the X electrode 22 and the waveform applied to the Y electrode 23 are the same as the waveforms shown in FIG.

  In the waveform applied to the address A electrode 29 in the present embodiment, the full pulse 13 in the sustain discharge period is set to a voltage (Va) different from the address pulses 7, 8 and 9. This is set appropriately with respect to the voltage of the sustain discharge pulse irrespective of the voltage of the discharge generated between the address electrode 29 and the Y electrode 23 because no discharge occurs in the entire pulse 13 in the sustain discharge period. This is because it is desirable. Note that the voltage Va of the full-surface pulse 13 and the address voltages Vr, Vg, Vb of each color may be substantially equal. As a result, the remaining two voltages excluding one of the address voltages Vr, Vg, Vb In some cases, the voltage Va of the whole-surface pulse 13 is substantially equal.

  As described above, the voltage applied to the address electrode 29 is changed according to the type of the phosphor or according to the discharge characteristics of the address electrode 29 including the characteristic difference of the phosphor, and the voltage of the entire pulse 13 is further changed. By appropriately setting the voltage of the sustain discharge pulse, the discharge operation can be stabilized.

  Next, a third embodiment will be described with reference to FIG. FIG. 10 is a time chart showing a part of the drive waveform of one subfield in the present embodiment. (A) is a part of the drive waveform applied to the X electrode 22, (b) is a part of the drive waveform applied to the Y electrode 23, for example, in the first row (Y1), c), (d), and (e) are applied to the electrodes (AR, AG, AB) of the address A electrode 29 corresponding to, for example, red (R), green (G), and blue (B) phosphors. Part of the driving waveform. Note that the same drive pulses as those in FIG. 1 are denoted by the same reference numerals as those in FIG. In FIG. 8, the waveform applied to the X electrode 22 and the waveform applied to the Y electrode 23 are the same as the waveforms shown in FIG.

  In the present embodiment, the waveform applied to the address A electrode 29 is V1 with respect to the ground potential (0 V) of the circuit even during the period in which the address pulses 14, 15, 16 and the full-face pulses 17, 18, 19 are not applied. Is set to the potential (bias potential). As a result, the voltages Vr2, Vg2, and Vb2 of the address pulses 14, 15, and 16 can be made lower than the voltages Vr, Vg, and Vb of the address pulse in the above-described embodiment, respectively. The load on the circuit can be reduced. The bias potential V1 is set lower than the discharge voltage between the Y electrode 23 and the bias potential V1.

  Next, a fourth embodiment will be described with reference to FIG. FIG. 11 is a time chart showing a part of the drive waveform of one subfield in the present embodiment. (A) is a part of the drive waveform applied to the X electrode 22, (b) is a part of the drive waveform applied to, for example, the first row (Y1) of the Y electrode 23, and (c) ( d) (e) is a part of the drive waveform applied to the electrodes (AR, AG, AB) of the address A electrode 29 corresponding to, for example, red (R), green (G), and blue (B) phosphors. is there. Note that the same drive pulses as those in FIG. In FIG. 9, the waveform applied to the X electrode 22 and the waveform applied to the Y electrode 23 are the same as the waveforms shown in FIG.

  Pulses (hereinafter referred to as address reset pulses) 50, 51, and 52 for performing address reset in accordance with the reset pulse 1 are applied to the address A electrode 29 in the reset period. The voltage Vr3, Vg3, Vb3 of each address reset pulse 50, 51, 52 is set so that the voltage difference from the voltage Vx of the reset pulse 1 exceeds the discharge voltage of each phosphor. When the discharge voltage of each phosphor is in the state shown in FIG. 11, the voltage of each address reset pulse 50, 51, 52 is set in the order of Vb3, Vr3, Vg3 from the highest. Thereby, at the rising edge of the reset pulse 1, a reset discharge is reliably generated between the X electrode 22 and the address A electrode 29, and the operation can be stabilized. When the address reset pulse voltages Vr3, Vg3, and Vb3 and the address pulse voltages Vr, Vg, and Vb are substantially equal in the same type of address electrode, there is an advantage that the power source can be shared.

  As described above, the discharge operation can be stabilized by applying to the address electrode 29 a voltage corresponding to the type of the light emitting medium such as a phosphor or the discharge characteristics of the address electrode 29 including the same. it can.

It is a figure which shows the drive waveform of one subfield in this invention. It is a disassembled perspective view which shows a part of structure of a plasma display panel. It is sectional drawing seen from the arrow A direction in FIG. It is sectional drawing seen from the arrow B direction in FIG. It is a schematic diagram which shows a panel electrode and a circuit structure. It is a figure which shows a part of wiring of an address electrode. It is a figure which shows the measured value of the discharge voltage of each fluorescent substance. It is a schematic diagram which shows the structure of 1 field. It is a figure which shows the drive waveform of one subfield in 2nd Embodiment. It is a figure which shows the drive waveform of one subfield in 3rd Embodiment. It is a figure which shows the drive waveform of one subfield in 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reset pulse 2 ... X scan pulse 3 ... X sustain discharge pulse 4 ... Y scan pulse 5 ... 1st sustain discharge pulse 6 ... Y sustain discharge pulse 7, 8, 9 ... Address pulse 10, 11, 12 ... Whole surface pulse 21 ... front glass substrate 22 ... X electrode 23 ... Y electrode 28 ... back glass substrate 29 ... address A electrode 31 ... partition wall 32 ... phosphor 34 ... X drive circuit 35 ... Y drive circuit 36 ... A drive circuit 37 ... R address driver 38 ... G address driver 39 ... B address driver 40 ... 1 field 41-48 ... first to eighth subfields 41a-48a ... reset period 41b-48b ... address period 41c-48c ... sustain discharge period 50, 51, 52 ... Address reset pulse

Claims (6)

Address is generated by a discharge between a sustain discharge for display and a parallel electrode group for generating a reset discharge for resetting all cells and an address electrode opposed to the electrode group and arranged in a substantially orthogonal direction. In a display device including a display unit that performs an operation,
At least one of the three address electrodes of red (R), green (G), and blue (B) provided with a different light-emitting medium for each electrode is defined as another address electrode corresponding to the discharge characteristics of the electrode. Driving at a different voltage, and controlling the reset discharge according to the discharge characteristics according to the difference between the voltage for reset and the voltage applied to the address electrode in accordance with the voltage for reset; and The display device is characterized in that the address discharge is controlled by applying a voltage different from that of the other address electrodes in response to the discharge characteristics in the address operation. The display device according to claim 1,
At least one of the three address electrodes of red (R), green (G), and blue (B) provided with a different light-emitting medium for each electrode is defined as another address electrode corresponding to the discharge characteristics of the electrode. Driving at a different voltage, and setting the difference between the reset voltage and the voltage applied to the address electrode in accordance with the reset voltage higher than the discharge start voltage corresponding to the discharge characteristics The display device is characterized in that the reset discharge is controlled, and the address discharge is controlled by applying a voltage different from that of the other address electrodes corresponding to the discharge characteristics in the address operation. An address is generated by a discharge between a sustain discharge for display and a parallel electrode group that generates a reset discharge that resets all cells and an address electrode that is opposed to the electrode group and arranged in a substantially orthogonal direction. In a display device including a display unit that performs an operation,
Each of the red (R), green (G), and blue (B) address electrodes provided with a different light-emitting medium for each electrode differs from the other address electrodes in accordance with the discharge characteristics of each electrode. The voltage or one type of address electrode is driven with a voltage different from that of the other address electrodes, and the difference is between the voltage for reset and the voltage applied to the address electrode in accordance with the voltage for reset. The reset discharge is controlled corresponding to the discharge characteristics, and also in the address operation, the voltage is different from the other address electrodes corresponding to the discharge characteristics, or one address electrode is different from the other address electrodes. A display device characterized in that a voltage is applied to control address discharge. The display device according to claim 3, wherein
Each of the red (R), green (G), and blue (B) address electrodes provided with a different light-emitting medium for each electrode differs from the other address electrodes in accordance with the discharge characteristics of each electrode. The voltage or one type of address electrode is driven with a voltage different from that of the other address electrodes, and the difference is between the voltage for reset and the voltage applied to the address electrode in accordance with the voltage for reset. The reset discharge is controlled by setting it higher than the discharge start voltage corresponding to the discharge characteristics, and also in the address operation, a voltage different from the other address electrodes or one type corresponding to the discharge characteristics. A display device, wherein a voltage different from that of other address electrodes is applied to an address electrode to control address discharge. Address is generated by a discharge between a sustain discharge for display and a parallel electrode group for generating a reset discharge for resetting all cells and an address electrode opposed to the electrode group and arranged in a substantially orthogonal direction. In a display device including a display unit that performs an operation,
At least one of the three address electrodes of red (R), green (G), and blue (B) provided with a different light-emitting medium for each electrode is defined as another address electrode corresponding to the discharge characteristics of the electrode. The address discharge is controlled by applying a voltage different from the other address electrodes corresponding to the discharge characteristics in the address operation, and controlling the address discharge in the sustain discharge period. A display device characterized by being applied to the display. Address is generated by a discharge between a sustain discharge for display and a parallel electrode group for generating a reset discharge for resetting all cells and an address electrode opposed to the electrode group and arranged in a substantially orthogonal direction. In a display device including a display unit that performs an operation,
Each of the red (R), green (G), and blue (B) address electrodes provided with a different light-emitting medium for each electrode differs from the other address electrodes in accordance with the discharge characteristics of each electrode. The address discharge is controlled by driving a voltage or one type of address electrode with a voltage different from that of the other address electrodes and applying a voltage different from that of the other address electrodes in accordance with the discharge characteristics in the address operation. The display device is characterized in that the voltage is applied to the address electrode even in the sustain discharge period.

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