# US 5,703,615 A · Method for driving matrix type flat panel display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,615 A - Document ID: US5703615A - Status: Granted - Kind: A - Application number: 08/457,305 - Filed: 1995-06-01 - Granted: 1997-12-30 - Earliest claimed: 1992-02-10 - Assignees: Fuji Photo Film Co., Ltd. - Inventors: Yoshihisa Usami - Web page: https://patentgrep.com/patent/US5703615A ## CPC - G09G 3/3629: {using liquid crystals having memory effects, e.g. ferroelectric liquid crystals} - G09G 2310/06: Details of flat display driving waveforms - G09G 2310/061: for resetting or blanking - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract There is provided a matrix-addressed driving method by which the image quality of a matrix type flat panel display device having bistability can be improved. Immediately after an application of an effective pulse of a selection signal, a counter-assist signal which has a polarity inverse to the polarity of the effective pulse of a selection signal for inverting the dark or bright state is added to the scanning signal. In lieu of this counter-assist signal or in addition to the counter-assist signal, an aid-assist signal having a polarity same as the polarity of the effective pulse of the selection signal may also be added at least one time before or after the application of the effective pulse. ## Claims ### Claim 1 In a method for driving a matrix type flat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional counter-assist signal which is applied immediately after said selection signal and before said non-selection signal; said counter-assist signal having a waveform such that a second part of said drive signal synthesized by a combination of said counter-assist signal and said ON or OFF display signal has a polarity inverse to a polarity of an effective pulse, said effective pulse being a third part of said drive signal synthesized by a combination of said selection signal and said ON or OFF display signal and which contributes to setting the particular bistable picture element to one of the bright or dark states; and a first time period of said counter-assist signal overlapping a second time period of a respective next selection signal for a respective next row of scanning electrodes. ### Claim 2 (depends on 1) The method of claim 1, wherein said counter-assist signal has a time period equal to that of said selection signal. ### Claim 3 (depends on 2) The method of claim 2, wherein an aid-assist signal is additionally applied immediately before the application of said selection signal, said aid-assist signal having a waveform such that a sixth part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as the polarity of said effective pulse. ### Claim 4 (depends on 2) The method of claim 2, wherein an aid-assist signal is additionally applied between the application of said selection signal and the application of said counter-assist signal, said aid-assist signal having a waveform such that a seventh part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as the polarity of said effective pulse. ### Claim 5 (depends on 1) The method of claim 1, wherein an aid-assist signal is additionally applied immediately before the application of of said selection signal, said aid-assist signal having a waveform such that a fourth part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as the polarity of said effective pulse. ### Claim 6 (depends on 1) The method of claim 1, wherein an aid-assist signal is additionally applied between the application of said selection signal and the application of said counter-assist signal, said aid-assist signal having a waveform such that a fifth part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as the polarity of said effective pulse. ### Claim 7 In a method for driving a matrix type flat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional aid-assist signal which is applied at least one time immediately before or immediately after the application of said selection signal; said aid-assist signal having a waveform such that a second part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as a polarity of an effective pulse, said effective pulse being a third part of said drive signal synthesized by a combination of said selection signal and said ON or OFF display signal and which contributes to setting the particular bistable picture element to one of the bright or dark states; and a first time period of said aid-assist signal overlapping a second time period of a respective adjacent selection signal for a respective adjacent row of scanning electrodes. ### Claim 8 (depends on 7) The method of claim 7, wherein a bias ratio, which is an absolute value of a ratio of a voltage of said first part of said drive signal synthesized by the combination of said non-selection signal and said ON or OFF display signal to a voltage of said third part of said drive signal synthesized by the combination of said selection signal and said ON or OFF display signal, is greater than 1/4. ### Claim 9 In a method for driving a matrix type flat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional aid-assist signal which is applied immediately after the application of said selection signal; said aid-assist signal having a waveform such that a second part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as a polarity of an effective pulse, said effective pulse being a third part of said drive signal synthesized by a combination of said selection signal and said ON or OFF display signal and which contributes to setting the particular bistable picture element to one of the bright or dark states; and a first time period of said aid-assist signal overlapping a second time period of a respective next selection signal for a respective next row of scanning electrodes. ### Claim 10 In a method for driving a matrix type flat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional aid-assist signal which is applied immediately before the application of said selection signal; said aid-assist signal having a waveform such that a second part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as a polarity of an effective pulse, said effective pulse being a third part of said drive signal synthesized by a combination of said selection signal and said ON or OFF display signal and which contributes to setting the particular bistable picture element to one of the bright or dark states; and a first time period of said aid-assist signal overlapping a second time period of a respective preceding selection signal for a respective preceding row of scanning electrodes. ### Claim 11 In a method for driving a matrix type flat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional aid-assist signal which is applied immediately before and immediately after the application of said selection signal; said aid-assist signal having a waveform such that a second part of said drive signal synthesized by a combination of said aid-assist signal and said ON or OFF display signal has a polarity same as a polarity of an effective pulse, said effective pulse being a third part of said drive signal synthesized by a combination of said selection signal and said ON or OFF display signal and which contributes to setting the particular bistable picture element to one of the bright or dark states; and a first time period of said aid-assist signal applied immediately before the application of the selection signal overlapping with a second time period of a respective preceding selection signal for a respective preceding row of scanning electrodes, and a third time period of said aid-assist signal applied immediately after the application of the selection signal overlapping with a fourth time period of a respective next selection signal for a respective next row of scanning electrodes. ### Claim 12 In a method for driving a matrix type fiat panel display device wherein a row of scanning electrodes intersects a row of signal electrodes at an intersecting point, wherein a bistable picture element is arranged at said intersecting point, wherein a scanning signal is applied to said row of scanning electrodes and an ON or OFF display signal is applied to said row of signal electrodes, wherein a drive signal is synthesized by a combination of said scanning signal and said ON or OFF display signal at said intersecting point, and wherein said scanning signal comprises: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal, (4) where a first part of said drive signal synthesized by a combination of said non-selection signal and said ON or OFF display signal has alternating positive and negative polarity pulses; the improvement comprising the step of providing said scanning signal with an additional signal which is applied immediately adjacent to the application of said selection signal, a first time period of said additional signal overlapping a second time period of a respective adjacent selection signal for a respective adjacent row of scanning electrodes. ### Claim 13 A method for driving a matrix type flat panel display device, comprising the steps of: intersecting a row of scanning electrodes with a row of signal electrodes at an intersecting point in the vicinity of a bistable picture element; applying a scanning signal to said row of scanning electrodes and an ON or OFF display signal to said row of signal electrodes, said scanning signal comprising: (1) a reset signal for resetting all said bistable picture elements along said row of scanning electrodes to one of a dark or bright state; (2) a selection signal for setting a particular bistable picture element at a particular intersecting point on said row of scanning electrodes to one of the bright or dark states from a reset state which has been reset by said reset signal; (3) a non-selection signal following the selection signal, said non-selection signal keeping the state of said particular bistable picture element set by said selection signal; and (4) an additional signal which is applied immediately adjacent to the application of said selection signal so that part of said additional signal overlaps with part of a respective adjacent selection signal for a respective adjacent row of scanning electrodes; and synthesizing a drive signal by combining said scanning signal and said ON or OFF display signal at said intersecting point so that part of said drive signal is synthesized by a combination of said non-selection signal and said ON or OFF display signal, said part having alternating positive and negative polarity pulses. ### Claim 14 (depends on 13) A method for driving a matrix type fiat panel display device according to claim 13, wherein said additional signal comprises at least one of a counter-assist signal and an aid-assist signal.