Method and apparatus for driving display panel

Abstract

An apparatus and method for driving a display panel, e.g., AC PDP, having a first substrate, at least one display line including first electrodes and second electrodes disposed in parallel with each other on the first substrate, a second substrate facing the first substrate, and third electrodes disposed on the second substrate and extending orthogonally to the first and second electrodes, in which write operation of the display data by a light emission is executed by carrying out a selective write discharge utilizing a memory function, are adapted to execute a write discharge for all cells and to execute an erase discharge for all cells before the selective write discharge, to thereby accumulate wall charges over the third electrodes in advance.

I claim:  
     
       1. A method for driving a display panel having a first substrate, at least one display line involving first electrodes and second electrodes disposed in parallel with each other on said first substrate, a second substrate facing said first substrate, and third electrodes disposed on said second substrate and extending orthogonally to said first and second electrodes, in which a display by means of a light emission and write operation of display data are executed by carrying out a write discharge utilizing a memory function for cells of said at least one display line and by carrying out a sustain discharge for sustaining said write discharge, wherein said method includes: 
       a step of executing a write discharge for all cells of at least one display line selected by either one of said first and second electrodes and by said third electrode with use of said first and second electrodes; and  
       a step of executing an erase discharge for all cells of said selected display line with use of said first and second electrodes, said two steps being adapted to be carried out before said write discharge utilizing said memory function is executed.  
     
     
       2. A method as set forth in claim  1 , wherein said display panel is composed of a set of display elements having a memory function, in which a frame that forms an image plane is made of a plurality of subframes, each of said subframes provides different luminance and includes an addressing period for rewriting display data and a sustain emission period for repeating an emission display operation according to said rewritten data, and the addressing and sustain emission periods are temporally separated from each other over said display elements, to provide said display elements with intensity levels and enable the adjustment of luminance of said image plane, wherein said method is adapted to increase or decrease the numbers of sustain emission operations of the respective subframes at the same ratio, thereby controlling the luminance of said image plane. 
     
     
       3. A method as set forth in claim  2 , wherein, when providing the display elements with intensity levels, the number of sustain emission operations of a given subframe is determined according to the number of sustain emission operations of another subframe whose weight of luminance is one rank heavier than that of the given subframe, namely, the number of sustain emission operations of a subframe whose weight of luminance is the heaviest among the subframes is determined at first, and according to this number, the number of sustain emission operations of another subframe whose weight of luminance is the second heaviest among the subframes is determined, and so on. 
     
     
       4. A method as set forth in claim  3 , wherein the number of sustain emission operations of a given subframe is set to be half of that of another subframe whose weight of luminance is one rank heavier than that of the given subframe. 
     
     
       5. A method as set forth in claim  4 , wherein fractions, if any, are rounded up or discarded when halving the number of sustain emission operations of a subframe whose weight of luminance is one rank heavier than that of a given subframe. 
     
     
       6. A method as set forth in claim  1 , wherein said display panel is constituted by an alternating current plasma display panel in which the memory function of each cell can be realized by wall charges accumulated by means of a write discharge. 
     
     
       7. A method as set forth in claim  2 , wherein said display panel is constituted by an alternating current plasma display panel in which the memory function of each cell can be realized by wall charges accumulated by means of a write discharge. 
     
     
       8. A method for driving a display panel which is constituted by an alternating current plasma display panel having a first substrate, at least one display line involving first electrodes and second electrodes disposed in parallel with each other on said first substrate, a second substrate facing said first substrate, and third electrodes disposed on said second substrate and extending orthogonally to said first and second electrodes, in which a display by means of a light emission and write operation of display data are executed by carrying out a write discharge utilizing a memory function for cells of said at least one display line and by carrying out a sustain discharge for sustaining said write discharge, said memory function being realized by wall charges accumulated by means of said write discharge, wherein said method includes: 
       a step of executing a write discharge for all cells of at least one display line selected by either one of first and second electrodes and by the third electrode with use of the first and second electrodes; and  
       a step of executing an erase discharge for all cells of said selected display line with use of said first and second electrodes, said two steps being adapted to be carried out before said write discharge utilizing said memory function is executed, and adapted to accumulate wall charges working effectively for said write discharge over at least said third electrodes in advance.  
     
     
       9. A method as set forth in claim  8 , wherein said first electrodes are connected all together, and said second electrodes disposed in the respective display lines are independent of one another, said method comprising: 
       sequentially selecting said display lines one by one, carrying out a write discharge in all cells of the selected display line with use of the first and second electrodes, carrying out or not carrying out a sustain discharge, applying an erase pulse to said second or first electrode of said selected display line, to carry out an erase discharge in all cells of the selected display line, and carrying out a write discharge in cells to be turned ON of said selected display line with use of said second and third electrodes, to thereby write said display data to said selected display line.  
     
     
       10. A method as set forth in claim  8 , wherein said first electrodes are connected all together, and said second electrodes disposed in the respective display lines are independent of one another, said method comprising: 
       sequentially selecting a plurality of the display lines, carrying out a write discharge in all cells of said selected display lines with use of said first and second electrodes, carrying out or not carrying out a sustain discharge, applying an erase pulse to said second or first electrodes of said selected display lines, to carry out an erase discharge in all cells of said selected display lines, and carrying out a write discharge in cells to be turned ON of said selected display lines with use of said second and third electrodes, to thereby write said display data to said selected display lines.  
     
     
       11. A method as set forth in claim  8 , wherein said first electrodes are connected all together, and said second electrodes disposed in the respective display lines are independent of one another, said method comprising: 
       carrying out a write discharge in all cells of all of said display lines with use of said first and second electrodes, carrying out or not carrying out a sustain discharge, applying an erase pulse to said second or first electrode of every display line, to carry out an erase discharge in all cells of all of said display lines, sequentially selecting said display lines one by one, carrying out a write discharge in cells to be turned ON of said selected display line with use of said second and third electrodes, to thereby write said display data to said selected display line, and after said display data are written to all of said display lines, carrying out a sustain discharge in said cells turned ON of all of said display lines with use of said first and second electrodes.  
     
     
       12. A method as set forth in claim  8 , wherein said first electrodes are connected all together, the second electrodes disposed in the respective display lines are independent of one another, said method comprising: 
       carrying out a write discharge in all cells of all of said display lines with use of said first and second electrodes, carrying out or not carrying out a sustain discharge, applying an erase pulse to said second or first electrode of every display line, to carry out an erase discharge in all cells of all of said display lines, sequentially selecting said display lines one by one, carrying out a write discharge in cells to be turned ON of said selected display line with use of said second and third electrodes, to thereby write said display data to said selected display line, immediately applying a sustain discharge pulse to said first electrode, to carry out a sustain discharge for stabilizing wall charges, and after said display data are written to all of said display lines, carrying out sustain discharge in said cells turned ON of all of said display lines with use of said first and second electrodes.  
     
     
       13. A method as set forth in claim  8 , wherein said display lines are grouped into a plurality of blocks, said first electrodes are connected together in each of the blocks, and said second electrodes disposed in the respective display lines are independent of one another. 
     
     
       14. A method as set forth in claim  8 , wherein said display lines are grouped into a plurality of blocks, said first electrodes are connected together in each of the blocks, and said second electrodes disposed in the respective display lines are independent of one another, said method comprising: 
       carrying out a write discharge in all cells of all of said display lines with use of said first and second electrodes, carrying out or not carrying out a sustain discharge, applying an erase pulse to said second or first electrode of every display line, to carry out an erase discharge in all cells of all of said display lines, sequentially selecting said display lines one by one, carrying out a write discharge in cells to be turned ON of said selected display line with use of said second and third electrodes, to thereby write said display data to said selected display line, immediately applying a sustain discharge pulse to said first electrode of the block that contains said cells just turned ON, to carry out a sustain discharge for stabilizing wall charges, and after display data are written to all of said display lines, carrying out a sustain discharge in said cells turned ON of all of said display lines with use of said first and second electrodes.  
     
     
       15. A method as set forth in claim  8 , wherein said display panel has a plurality of second electrodes that are sequentially selected and driven line by line and first electrodes that are driven by a single driver circuit and are disposed between every two adjacent ones of said second electrodes, and method comprising: 
       setting a voltage applied to said second electrodes of unselected lines to be lower than the potential of a sustain discharge pulse for executing said sustain discharge, or equal to an addressing voltage for executing said write discharge when the write operation of display data is executed by carrying out the write discharge utilizing said memory function.  
     
     
       16. A method as set forth in claim  9 , wherein an erase discharge is carried out with use of said first and second electrodes, just before said write discharge for all cells is executed. 
     
     
       17. A method as set forth in claim  10 , wherein an erase discharge is carried out with use of said first and second electrodes, just before said write discharge for all cells is executed. 
     
     
       18. A method as set forth in claim  11 , wherein an erase discharge is carried out with use of said first and second electrodes, just before said write discharge for all cells is executed. 
     
     
       19. A method as set forth in claim  12 , wherein an erase discharge is carried out with use of said first and second electrodes, just before said write discharge for all cells is executed. 
     
     
       20. A method as set forth in claim  14 , wherein an erase discharge is carried out with use of said first and second electrodes, just before said write discharge for all cells is executed. 
     
     
       21. A method as set forth in claim  9 , wherein a sustain discharge is carried out by applying a narrow pulse such that an erase discharge is not executed, immediately after said write discharge for all cells is executed. 
     
     
       22. A method as set forth in claim  10 , wherein a sustain discharge is carried out by applying a narrow pulse such that an erase discharge is not executed, immediately after said write discharge for all cells is executed. 
     
     
       23. A method as set forth in claim  11 , wherein a sustain discharge is carried out by applying a narrow pulse such that an erase discharge is not executed, immediately after said write discharge for all cells is executed. 
     
     
       24. A method as set forth in claim  12 , wherein a sustain discharge is carried out by applying a narrow pulse such that an erase discharge is not executed, immediately after said write discharge for all cells is executed. 
     
     
       25. A method as set forth in claim  14 , wherein a sustain discharge is carried out by applying a narrow pulse such that an erase discharge is not executed, immediately after said write discharge for all cells is executed. 
     
     
       26. An apparatus for driving a display panel having a first substrate, at least one display line involving first electrodes and second electrodes disposed in parallel with each other on said first substrate, a second substrate facing said first substrate, and third electrodes disposed on said second substrate and extending orthogonally to said first and second electrodes, in which a display by means of a light emission and write operation of display data are executed by carrying out a write discharge utilizing a memory function for cells of said at least one display line and by carrying out a sustain discharge for sustaining said write discharge, wherein said apparatus comprises: 
       driving means which supplies a plurality of driving voltage pulses for executing write operation of said display data for said first, second and third electrodes; and  
       control means which controls a sequence of supplying these plurality of driving voltage pulses, and wherein said control means is operative to apply a write pulse for executing a write discharge for all cells of at least one display line selected by either one of said first and second electrodes and by said third electrode with use of said first and second electrodes, and to apply an erase pulse for executing an erase discharge for all cells of said selected display line with use of said first and second electrodes, before said write discharge utilizing said memory function is carried out.  
     
     
       27. An apparatus as set forth in claim  26 , wherein said apparatus is composed of a set of display elements having a memory function, in which a frame that forms an image plane is made of a plurality of subframes, each of the subframes provides different luminance and includes an addressing period for rewriting display data and a sustain emission period for repeating an emission display operation according to said rewritten data, and said addressing and sustain emission periods are temporally separated from each other over said display elements, to provide said display elements with intensity levels and enable the adjustment of luminance of said image plane, sand wherein said apparatus further comprises: 
       first means for determining the number of sustain emission operations of a subframe whose weight of luminance is the heaviest among the subframes; and  
       second means for determining, according to the above determined number, the number of sustain emission operations of a subframe whose weight of luminance is the next heaviest among said subframes.  
     
     
       28. An apparatus as set forth in claim  27 , wherein said apparatus further comprises means for stopping operations carried out in a subframe, if the number of sustain emission operations to be carried out in this subframe is zero as a result of luminance adjustment carried out by said first and second means. 
     
     
       29. An apparatus as set forth in claim  28 , wherein said apparatus further comprises: 
       means for holding data according to which the number of sustain discharge operations of the next subframe is determined;  
       means for counting the number of sustain discharge operations carried out in the present subframe;  
       means for comparing said counted value with said held data; and  
       means for providing an instruction to start the next subframe if the comparison means indicates agreement.  
     
     
       30. An apparatus as set forth in claim  27 , wherein said first means has means for optionally setting the number of sustain emission operations of a subframe whose weight of luminance is the heaviest. 
     
     
       31. An apparatus as set forth in claim  26 , wherein said display panel is an alternating current plasma display panel, and the memory function of each cell of said display panel is achieved by wall charges accumulated by a write discharge. 
     
     
       32. An apparatus as set forth in claim  27 , wherein said display panel is an alternating current plasma display panel, and the memory function of each cell of said display panel is achieved by wall charges accumulated by a write discharge. 
     
     
       33. An apparatus for driving a display panel which is constituted by an alternating current plasma display panel having a first substrate, at least one display line involving first electrodes and second electrodes disposed in parallel with each other on said first substrate, a second substrate facing said first substrate, and third electrodes disposed on said second substrate and extending orthogonally to said first and second electrodes, in which a display by means of a light emission and write operation of display data are executed by carrying out a write discharge utilizing a memory function for cells of said at least one display line and by carrying out a sustain discharge for sustaining said write discharge, said memory function being realized by wall charges accumulated by means of a write discharge, wherein said apparatus comprises: 
       driving means which supplies a plurality of driving voltage pulses for executing write operation of said display data for said first, second and third electrodes; and  
       control means which controls a sequence of supplying these plurality of driving voltage pulses, wherein said control means is operative to apply a write pulse for executing a write discharge for all cells of at least one display line selected by either one of said first and second electrodes and by said third electrode with use of said first and second electrodes, and to apply an erase pulse for executing an erase discharge for all cells of said selected display line with use of said first and second electrodes, before said write discharge utilizing said memory function is carried out, so that wall charges working effectively for said write discharge are accumulated over at least said third electrodes in advance.  
     
     
       34. An apparatus as set forth in claim  33 , wherein said control means is operative to sequentially select the display lines one by one, to apply a write pulse for carrying out a write discharge in all cells of said selected display line with use of said first and second electrodes, to apply a sustain discharge pulse selectively for carrying out a sustain discharge, to apply an erase pulse to said second or first electrode of said selected display line, to apply an erase pulse for carrying out an erase discharge in all cells of the selected display line, and to carry out a write discharge in cells to be turned ON of said selected display line with use of said second and third electrodes, to thereby write display data to said selected display line, by means of said driving means. 
     
     
       35. An apparatus as set forth in claim  33 , wherein said control means is operative to sequentially select a plurality of the display lines, to apply a write pulse for carrying out a write discharge in all cells of said selected display lines with use of said first and second electrodes, to apply a sustain pulse selectively for carrying out a sustain discharge, to apply an erase pulse to said second or first electrodes of said selected display lines, apply an erase pulse for to carrying out an erase discharge in all cells of said selected display lines, and to apply a write pulse for carrying out a write discharge in cells to be turned ON of the selected display lines with use of said second and third electrodes, to thereby write said display data to said selected display lines, by means of said driving means. 
     
     
       36. An apparatus as set forth in claim  33 , wherein said display panel comprises an insulation layer, which separates said third electrode from a discharge space formed between said third electrode and said first and second electrodes, so that said wall charges can be accumulated on said insulation layer. 
     
     
       37. Apparatus for driving a display panel which is constituted by an alternating current plasma display panel having a first substrate, a plurality of display lines having first electrodes and second electrodes disposed to extend alongside one another on said first substrate, a second substrate facing said first substrate, and third electrodes disposed on said second substrate and crossing said first and second electrodes, in which a write discharge for executing a write operation of display data is carried out for cells of said at least one display line selected by one of said first and second electrodes and by said third electrodes, and a sustain discharge for executing a display of said display data is carried out by utilizing a memory function, said memory function being realized by wall charges accumulated by a write discharge, wherein said apparatus comprises: 
       
         a plurality of driver circuits which supply plural kinds of driving voltage pulses to said first, second and third electrodes for executing a write operation of said display data by said electrodes; and  
       
       
         a sequence controller which controls a sequence of supplying said plural kinds of driving voltage pulses to said electrodes, said sequence controller including a first control circuit for causing said plurality of driver circuits to apply a write pulse across first and second electrodes to execute a write discharge for all cells of a selected display line, and a second circuit for causing said plurality of driver circuits to apply an erase pulse across first and second electrodes for executing an erase discharge for all cells of said selected display line, said sequence controller being operable for causing said plurality of driver circuits to apply said write and erase pulses before said write operation is carried out in cells of said selected display line, so that wall charges working effectively for said write operation are accumulated in advance of said write operation over at least said third electrodes. 
       
     
     
       38. Apparatus as set forth in claim  37 , 
       
         wherein said write discharge for executing said write operation is sequentially carried out for cells of each of a plurality of selected display lines with use of said second and third electrodes for every selected display line one by one, and said write operation of display data is executed, and after said write operation of display data is completed for all the selected display lines, said sustain discharge is carried out for cells of all the selected display lines with use of said first and second electrodes, and  
       
       
         wherein said control circuit allows said plurality of driver circuits to apply said write pulse for executing said write discharge for all cells of all display lines with use of said first and second electrodes, to apply or not to apply a sustain discharge pulse selectively for executing said sustain discharge, to apply said erase pulse for executing said erase discharge for all cells corresponding to said second electrodes or said first electrodes on all display lines, to apply said write pulse for carrying out said write operation for cells of each of said selected display lines with use of said second and third electrodes for every selected display lines one by one, and to apply said sustain discharge for cells of all display lines with use of said first and second electrodes. 
       
     
     
       39. A method for driving an alternating current plasma display panel having a first substrate, a plurality of display lines, each of which display lines comprises a first electrode and a second electrode disposed to extend alongside one another on said first substrate, a second substrate facing said substrate, and a plurality of third electrodes disposed on said second substrate so as to extend across said first and second electrodes, said display lines each including a plurality of cells formed at respective areas where a corresponding third electrode crosses the first and second electrodes of the panel, said method comprising: 
       
         selecting a display line from said plurality thereof for writing data;  
       
       
         choosing a cell of the selected display line;  
       
       
         conducting a write discharge for writing data in the chosen cell by conducting an addressing procedure comprising applying a selective write discharge voltage between said corresponding third electrode of the chosen cell and one of said second electrodes;  
       
       
         conducting and maintaining a sustain discharge in the chosen cell for displaying data by applying a sustain discharge voltage between said first electrode and said second electrode; and  
       
       
         applying a predetermined voltage to a second electrode of a display line which has not been selected for writing data during said addressing procedure such that the resulting potential difference between said second electrode of a display line which has not been selected for writing data and a second electrode of a display line which has been selected for writing data is less than the potential difference brought about between said first and second electrodes for executing said sustain discharge, or equal to a voltage applied to each of said third electrodes for executing said selective write discharge. 
       
     
     
       40. An apparatus for driving a display panel which is constituted by an alternating current plasma display panel having a first substrate, a plurality of display lines, each including first and second electrodes disposed to extend alongside one another on said first substrate, a second substrate facing said first substrate, and a plurality of third electrodes disposed on said second substrate so as to cross said first and second electrodes, said display lines each including a plurality of cells formed at respective areas where a third electrode crosses first and second electrodes, in which apparatus a write discharge for executing a write operation of display data brought about using a selected third electrode and one of said second electrodes is carried out for selected cells of at least one display line selected by one of said second electrodes and by said third electrodes, and a sustain discharge for executing a display of said display data is carried out utilizing a memory function, wherein said apparatus comprises: 
       
         a plurality of selection circuits which are respectively connected to second electrodes, and which supply second electrodes corresponding to said selected cells of said at least one display line with a write pulse for executing said write discharge; and  
       
       
         a common driver circuit connected to said selection circuits, and which supplies said second electrodes corresponding to said selected cells with a sustain discharge pulse for executing said sustain discharge,  
       
       
         wherein a voltage applied between a second electrode of an unselected display line and a second electrode of a selected display line during said write operation is set at a level that is lower than a voltage applied between first and second electrodes for executing said sustain discharge, or is equal to a potential applied to said third electrodes for executing a write discharge. 
       
     
     
       41. An apparatus as set forth in claim  40 , wherein at least one of said selection circuits includes a pair of switching elements connected in a push- pull form, respectively.   
     
     
       42. An apparatus as set forth in claim  40 , wherein each of said selection circuits includes a pair of switching elements connected in a push- pull form, respectively.   
     
     
       43. An apparatus as set forth in claim  40 , wherein said driver circuit includes a pair of switching elements connected in a push- pull form, respectively.   
     
     
       44. An apparatus as set forth in claim  41 , wherein said driver circuit includes a pair of switching elements connected in a push- pull form, respectively.   
     
     
       45. An apparatus as set forth in claim  42 , wherein said driver circuit includes a pair of switching elements connected in a push- pull form, respectively.   
     
     
       46. An apparatus as set forth in claim  45 , wherein said driver circuit is connected to one side of said pair of switching elements in each of said selection circuits. 
     
     
       47. An apparatus as set forth in claim  45 , wherein a first diode is connected to one side of said pair of switching elements in each of said selection circuits, and wherein a potential applied to each of said second electrodes on said unselected display lines is supplied to each of said second electrodes, via said first diode. 
     
     
       48. An apparatus as set forth in claim  46 , wherein a first diode is connected to another side of said pair of switching elements in each of said selection circuits, and wherein a potential applied to each of said second electrodes on said unselected display lines is supplied to each of said second electrode, via said first diode. 
     
     
       49. An apparatus as set forth in claim  47 , wherein each of said selection circuits includes a second diode which is connected in parallel with another side of said pair of switching elements, and wherein said sustain discharge pulse applied to each of said second electrodes is supplied to each of said second electrodes, via said second diode. 
     
     
       50. An apparatus as set forth in claim  48 , wherein each of said selection circuits includes a second diode which is connected in parallel with said one side of said pair of switching elements, and wherein said sustain discharge pulse applied to each of said second electrodes is supplied to each of said second electrodes, via said second diode. 
     
     
       51. A circuit for driving a display panel having a plurality of display lines including respective electrodes, said circuit comprising: 
         a plurality of selection circuits, each including a pair of first switching elements connected in a push - pull form;    
         a driver circuit including a pair of second switching elements connected in a push - pull form, which is connected to one side of said pair of first switching elements and supplies a sustain discharge pulse necessary for a sustain discharge for executing a display of display data on at least one selected display line of said panel to each of said electrodes, via said selection circuits; and    
       
         a first diode which is connected to another side of said pair of first switching elements, and supplies a given voltage applied to unselected display lines of said panel to each of said electrodes, via said first diode. 
       
     
     
       52. A circuit as set forth in claim  51 , wherein each of said selection circuits includes a second diode which is connected in parallel with one side of said pair of first switching elements, and wherein said sustain discharge pulse is supplied to said second diode. 
     
     
       53. A method for driving a display panel which is constituted by an alternating current plasma display panel having first electrodes and second electrodes each constituting a pair for carrying out discharge, each pair of said first and second electrodes disposed to extend alongside one another and corresponding to a display line, and third electrodes disposed crossing said first and second electrodes, and cells formed at intersections of said first and second electrodes with said third electrodes, wherein said method includes: 
       
         sequentially selecting a second electrode corresponding to each display line during an addressing period, and writing display data for said each display line; and  
       
       
         repeatedly applying sustain discharge pulses during a sustain discharge period, to maintain a sustain discharge to emit light,  
       
       
         wherein a potential difference between a second electrode of each display line which has not been selected and the second electrode of each display line which has been selected during the addressing period, is set to be lower than a difference between a maximum voltage of each of the sustain discharge pulses and a minimum voltage thereof. 
       
     
     
       54. A method for driving a display panel which is constituted by an alternating current plasma display panel having first electrodes and second electrodes each constituting a pair for carrying out discharge, each pair of the first and second electrodes disposed to extend alongside one another and corresponding to a display line, and third electrodes disposed crossing the first and second electrodes, and two first electrodes disposed adjacently and two second electrodes disposed adjacently, and the two adjacent ones of said first electrodes and the two adjacent ones of said second electrodes disposed alternately, wherein said method includes: 
       
         sequentially selecting a second electrode corresponding to each display line during an addressing period, and writing display data for said each display line; and  
       
       
         repeatedly applying sustain discharge pulses during a sustain discharge period, to maintain a sustain discharge to emit light,  
       
       
         wherein a potential difference between a second electrode of each display line which has not been selected and the second electrode of each display line which has been selected during the addressing period, is set to be lower than a difference between a maximum voltage of each of the sustain discharge pulses and a minimum voltage thereof. 
       
     
     
       55. A method as set forth in claim  54 , wherein the first electrodes are connected all together, and the second electrodes are disposed independent of one another.