Liquid-crystal display device and method of driving liquid-crystal display device
OwnerYoshifumi Sekiguchi, Tsunenori Yamamoto +1inventors
InventorsYoshifumi Sekiguchi, Tsunenori Yamamoto, Shoichi Hirota
Life of this patent
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Abstract
A liquid-crystal display device and a method of driving the same which can suppress flicker to maintain an enhanced quality of picture, and can reduce its power consumption. A backlight unit is turned ON and OFF a plurality of times in synchronism with a frame period having a scanning period and a hold period longer than the scanning period. One turning ON and OFF period of the backlight corresponds to a backlight period having a length of 1/60 seconds or smaller. The backlight unit is turned ON and OFF four times in four backlight periods within one frame period. Thus, the display device can suppress flicker and reduce its power consumption.
Claims28
A method for driving a liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising the steps of:
- providing a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length corresponding nearly to said scanning period or longer;
- setting a sum of said scanning period and said hold period as a frame period, said frame period being continuously repeated, and having a length not shorter than 1/60 seconds;
- providing a plurality of backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period, a sum of lengths of said plurality of backlight periods being equal to a length of said frame period;
- and setting the OFF period of said backlight unit to be longer than the ON period of said backlight unit in said scanning period.
A method for driving a liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising the steps of:
- providing a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length corresponding nearly to said scanning period or longer;
- setting a sum of said scanning period and said hold period as a frame period, said frame period being continuously repeated, said frame period having a length not shorter than 1/60 seconds, providing a plurality of backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period, a sum of lengths of said plurality of backlight periods being equal to a length of said frame period;
- and when a period after scanning is started until nearly half of all the gate lines to be scanned is scanned is set to be a preceding half of the scanning period and a period until the remaining gate lines are scanned is set to be a succeeding half of the scanning period, setting at least the ON period of said backlight unit in the preceding half of said scanning period, and setting at least the OFF period of said backlight unit in the succeeding half of said scanning period.
A method for driving a liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising the steps of:
- providing a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length corresponding nearly to said scanning period or longer;
- setting a sum of said scanning period and said hold period as a frame period, said frame period being continuously repeated, said frame period having a length not shorter than 1/60 seconds;
- providing backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period being continuously repeated;
- turning said backlight unit ON and OFF at least once in said hold period;
- and setting the OFF period of said backlight unit to be longer than the OFF period of said backlight unit in the scanning period.
A method for driving a liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising the steps of:
- proving a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length corresponding nearly to said scanning period or longer, a sum of said scanning period and said hold period corresponds to a frame period, said frame period being continuously repeated, said frame period is set to have a length not shorter than 1/60 seconds, providing backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period being continuously repeated;
- turning said backlight unit ON and OFF at least once in said hold period;
- and when a period after scanning is started until nearly half of all the gate lines to be scanned is scanned is set to be a preceding half of the scanning period and a period until the remaining gate lines are scanned is set to be a succeeding half of the scanning period, setting at least the ON period of said backlight unit in the preceding half of said scanning period, and at least the OFF period of said backlight unit in the succeeding half of said scanning period.
A liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light,
- wherein a light source of said backlight unit is a light emitting diode,
- a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period are provided,
- said hold period has a length corresponding nearly to said scanning period or longer, a sum of said scanning period and said hold period corresponds to a frame period, said frame period is continuously repeated, said frame period is set to have a length not shorter than 1/60 seconds, a plurality of backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period are provided,
- a sum of lengths of said plurality of backlight periods is equal to a length of said frame period, and
- a control circuit for controlling an on-off timing of the backlight is provided so that the OFF period of said backlight unit is longer than the ON period of said backlight unit in said scanning period.
A liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light,
- wherein a light source of said backlight unit is a light emitting diode, a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period are provided, said hold period has a length corresponding nearly to said scanning period or longer, a sum of said scanning period and said hold period corresponds to a frame period, said frame period is continuously repeated, said frame period is set to have a length not shorter than 1/60 seconds, a plurality of backlight periods each including an OFF period of said backlight unit and an ON period subsequent to said OFF period are provided, a sum of lengths of said plurality of backlight periods is equal to a length of said frame period, a period after scanning is started until nearly half of all the gate lines to be scanned is scanned is set to be a preceding half of the scanning period, a period until the remaining gate lines are scanned is set to be a succeeding half of the scanning period, a control circuit for controlling an on-off timing of the backlight is provided so that at least the ON period of said backlight unit is in the preceding half of said scanning period, and at least the OFF period of said backlight unit is in the succeeding half of said scanning period.
A liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light,
- wherein a scanning period for providing image data from said data line to said pixels and a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period are provided, said hold period has a length corresponding nearly to said scanning period or longer, a sum of said scanning period and said hold period corresponds to a frame period, said frame period is continuously repeated, said frame period is set to have a length not shorter than 1/60 seconds, a dynamic range of a voltage to be applied to said data line can be adjusted, said dynamic range is made narrow in an arbitrary frame and simultaneously the quantity of light irradiated by the backlight unit in one frame is made small.
A method for driving a liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising the steps of:
- setting a plurality of backlight periods each having an OFF period of said backlight unit and an ON period subsequent to said OFF period in the frame period in synchronism with a frame period, said frame period having a scanning period for providing image data from said data line to said pixels and also having a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length longer than said scanning period, and driving said backlight unit intermittently in said plurality of backlight periods.
A liquid-crystal display device comprising a liquid crystal panel and a backlight unit, said liquid crystal panel including a pair of substrates, a liquid crystal layer held between said pair of substrates, data and gate lines for applying an electric field to said liquid crystal layer, a plurality of active elements connected at intersections of said data and gate lines, and pixels driven by said active elements, said backlight unit intermittently turning ON and OFF to intermittently irradiate said liquid crystal panel with light, comprising:
- a timing control circuit operable so that a plurality of backlight periods each having an OFF period of said backlight unit and an ON period subsequent to said OFF period are set in the frame period in synchronism with a frame period, said frame period having a scanning period for providing image data from said data line to said pixels and also having a hold period for putting all of said gate lines in a non-scan state immediately after said scanning period, said hold period having a length longer than said scanning period, and said backlight unit is intermittently driven in said plurality of backlight periods.
Dependencies are inferred from the claim text.