Liquid crystal display, its driving method, and driving circuit and power supply used therefor

Claim 2

Drive method for a liquid crystal display device of claim 1 wherein the absolute value of the voltage difference of saturation voltage Vsat and threshold voltage Vth of the chiral nematic liquid crystal change with dependence on the value of m and the value of m is selected from an area that makes the absolute value of said voltage difference small.

Claim 3

Drive method for a liquid crystal display device of claim 2 wherein the absolute value of the ON voltage applied to the chiral nematic liquid crystal in said selection period is set larger than the absolute value of said saturation voltage Vsat of the chiral nematic liquid crystal by at least an allowable margin and the absolute value of the OFF voltage applied to the chiral nematic liquid crystal in said selection period is set smaller than the absolute value of said threshold voltage Vth of the chiral nematic liquid crystal within an allowable margin.

Claim 4

Drive method for a liquid crystal display device of claims 1 to 3 wherein a delay period is provided in said scanning signal between said reset period and said selection period, and the voltage level in said delay period of said scanning signal is set the same as the voltage level of said non-selection period.

Claim 5

Drive method for a liquid crystal display device of claims 1 to 4 wherein said data signal is set every said selection period to a data voltage level containing the voltage level of either the ON voltage level or the OFF voltage level and four voltage levels are set for application of positive and negative ON selection voltages and positive and negative OFF selection voltages to said liquid crystal as said data voltage levels of said data signal, said scanning signal is set to the reset voltage level in said reset period, to the selection voltage level in said selection period, and to the non-selection voltage level in said non-selection period, two types of voltage levels are set for application of positive and negative reset voltages to said liquid crystal as said reset voltage levels in said reset period, two types of voltage levels are set for application of said positive and negative selection voltages to said liquid crystal as said selection voltage levels in said selection period, and two types of voltage levels are set to provide bias voltage levels as said non-selection voltage levels in said non-selection period, and said liquid crystal is driven using a total of eight voltage levels by using said two types of reset voltage levels and said two types of selection voltage levels in common.

Claim 6

Drive method for a liquid crystal display device of claim 5 wherein said eight voltage levels comprise the four levels (V1, V2, V3, V4; V1 < V2 < V3 < V4) of a first group on the low-voltage side including ground voltage level V1 and the four levels (V5, V6, V7, V8; V4 < V5 < V6 < V7 < V8) of a second group on the high-voltage side.

Claim 7

Drive method for a liquid crystal display device of claim 6 wherein said scanning signal takes on a waveform having the voltage level of V1 and V8 in said reset period, takes on the voltage level of V1 or V8 in said selection period, and takes on a waveform having the voltage level of V3 and V6 in said non-selection period, and said data signal is a waveform including a pulse whose peak value changes to the voltage level of V2 and V4 and a pulse whose peak value changes to the voltage levels of V5 and V7.

Claim 8

Drive method for a liquid crystal display device of claim 7 wherein the relationship V4 - V3 = V3 - V2 = V7 - V6 = V6 - V5 is set.

Claim 9

Drive method for a liquid crystal display device of claim 6 wherein said scanning signal takes on a waveform having the voltage levels of V4 and V5 in said reset period, takes on the voltage levels of V4 or V5 in said selection period, and takes on a waveform having the voltage levels of V2 and V7 in said non-selection period, and said data signal is a waveform including a pulse whose peak value changes to the voltage levels of V1 and V3 and a pulse whose peak value changes to the voltage levels of V6 and V8.

Claim 10

Drive method for a liquid crystal display device of claim 9 wherein the relationship V3 - V2 = V2 - V1 = V8 - V7 = V7 - V6 is set.

Claim 11

Drive method for a liquid crystal display device of claims 1 to 10 wherein the value m which determines the reversal time is set to a value such that the value resulting from dividing the number of display scanning lines by m is an integer.

Claim 12

Drive method for a liquid crystal display device of claims 1 to 10 wherein the value m which determines the reversal time is set to a value such that the value resulting from dividing the number of display scanning lines by m is not an integer.

Claim 13

Drive method for a liquid crystal display device of claims 1 to 11 wherein mH < 1 frame period is set, and when the voltage at the start of the nth frame (n is an integer) is a voltage level of said first group, the start of the (n + 1)th frame is a voltage level of the second group, when the voltage at the start of the nth frame is a voltage level of said second group, the start of the (n + 1)th frame is a voltage level of the first group, and reversal every mH and reversal every frame unit are overlapped and repeated.

Claim 14

Drive method for a liquid crystal display device of claim 7 or 8 wherein mH < 1 frame period is set, in the nth frame (n is an integer), the ON selection voltage level of said data signal is set to V4 of the first group and the OFF selection voltage level is set to V2 of the first group, and said reset voltage level at the start of said scanning signal is set to V8 and said selection voltage level is set to V1, in the following (n + 1)th frame, the ON selection voltage level of said data signal is set to V5 of said second group and the OFF selection voltage level is set to V7 of the second group, and said reset voltage level at the start of said scanning signal is set to V1 and said selection voltage level is set to V8, and reversal every mH and reversal every frame unit are overlapped and repeated.

Claim 15

Drive method for a liquid crystal display device of claim 9 or 10 wherein mH < 1 frame period is set, in the nth frame In is an integer), the ON selection voltage level of said data signal is set to V1 of said first group and the OFF selection voltage level is set to V3 of the first group, and said reset voltage level at the start of said scanning signal is set to V5 and said selection voltage level is set to V4, in the following (n + 1)th frame, the ON selection voltage level of said row electrode signal is set to V8 of the second group and the OFF selection voltage level is set to V6 of the second group, and said reset voltage level at the start of said data signal is set to V4 and said selection voltage level is set to V5, and reversal every mH and reversal every frame unit are overlapped and repeated.

Claim 16

Drive method for a liquid crystal display device of claims 6 to 12 wherein the voltage level difference between voltage level V4 of said first group and voltage level V5 of said group is made large and the absolute value of said reset voltage applied to said liquid crystal in said reset period is set large.

Claim 17

Liquid crystal display device comprising liquid crystal panel made up of chiral nematic liquid crystal having at least two stable states and infused between a first substrate whereon are formed a plurality of scanning electrodes and a second substrate whereon are formed a plurality of data electrodes, scanning electrode drive circuit that outputs scanning signals having at least a reset period, a selection period and a non-selection period in one frame to each of said scanning electrodes, data electrode drive circuit that outputs data signals to each of said data electrodes, and power supply circuit that outputs a total of eight or more voltage levels made up of a plurality of levels of a first group on the low-voltage side and a plurality of levels of a second group on the high-voltage side as potentials of said scanning signal and said data signal, wherein said scanning electrode drive circuit and said data electrode drive circuit alternately change the voltage levels of said scanning signal and said data signal between said first group and second group every mH (where, m is an integer that is 2 or greater and mH _ 1 frame period), which is an integral multiple of the unit time (1H) equivalent to said selection period of said scanning signal, said scanning electrode drive circuit selects the voltage level of said reset period in said scanning signal from said second group when said data signal is a voltage level of said first group and selects the voltage level of said reset period in said scanning signal from said first group when said data signal is a voltage level of said second group, selects each of the voltage levels of said selection period and non-selection period in said scanning signal from the same first group when said data signal is a voltage level of said first group and selects each of the voltage levels of said selection period and non-selection period in said scanning signal from the same second group when said data signal is a voltage level of said second group, and the polarity of the voltage applied to said liquid crystal is reversed every mH.

Claim 18

Drive circuit for a liquid crystal display device that drives said liquid crystal and is connected to a liquid crystal panel comprising chiral nematic liquid crystal having at least two stable states and infused between a first substrate whereon are formed a plurality of scanning electrodes and a second substrate whereon are formed a plurality of data electrodes, and power supply circuit that outputs a total of eight or more voltage levels made up of a plurality of levels of a first group on the low-voltage side and a plurality of levels of a second group on the high-voltage side as drive potentials for said liquid crystal, and having scanning electrode drive circuit that outputs scanning signals having at least a reset period, a selection period and a non-selection period in one frame to each of said scanning electrodes, and data electrode drive circuit that outputs data signals to each of said data electrodes, wherein said scanning electrode drive circuit and said data electrode drive circuit alternately change the voltage levels of said scanning signal and said data signal between said first group and second group every mH (where, m is an integer that is 2 or greater and mH _ 1 frame period), which is an integral multiple of the unit time (1H) equivalent to said selection period of said scanning signal, said scanning electrode drive circuit selects the voltage level of said reset period in said scanning signal from said second group when said data signal is a voltage level of said first group and selects the voltage level of said reset period in said scanning signal from said first group when said data signal is a voltage level of said second group, selects each of the voltage levels of said selection period and non-selection period in said scanning signal from the same first group when said data signal is a voltage level of said first group and selects each of the voltage levels of said selection period and non-selection period in said scanning signal from the same second group when said data signal is a voltage level of said second group, and the polarity of the voltage applied to said liquid crystal is reversed every mH.

Claim 19

Power supply circuit device for a liquid crystal display device, which generates an even number of a total of 8 or more voltage levels (V1, V2, ..., V k/2 , ...,Vk -1 , V k ; V1 < V2 < ...< V k/2 < ... < V k-1 < V k ), including ground voltage level V1, for applying the voltage of the difference signal of the scanning signal and the data signal to the liquid crystal, has means for generating maximum voltage level V k , means for generating potential difference V B , which becomes the reference for generating voltage levels V2 to V k-1 , not including the maximum voltage level V k and ground voltage level V1, calculation means for calculating and outputting voltage levels V2 to V k-1 based on said potential difference V B , and changing means for changing the value of said potential difference V B from outside, whereby it becomes possible to adjust each voltage level (V2, ..., V k-1 ), except said ground voltage level V1 and maximum voltage level V k , simultaneously by changing said potential difference V B .

Claim 20

Power supply circuit device for a liquid crystal display device of claim 19 wherein the means that generates said potential difference V B generates said potential difference V B based on said maximum voltage level V k .

Claim 21

Power supply circuit device for a liquid crystal display device of claim 19 or 20 wherein said calculation means has a plurality of calculation circuits to which said voltage level V B is input and that calculate and output each of the voltage levels (V2, ..., V k/2 ) from among the plurality of levels (V1, V2, ..., V k/2 ), except said ground voltage level V1, of the first group on the low-voltage side of said eight or more voltage levels, and a plurality of subtraction circuits that generate each of the voltage levels (V k-1 , ..., V k/2 + 1 ) of the voltage levels (V k/2 + 1 , V k/2 + 2 , ..., V k-1 , V k ), except maximum voltage level V k , of the second group on the high voltage side by subtracting the respective outputs (V2, ..., V k/2 ) of said amplification means from said maximum voltage level V k .

Claim 22

Power supply circuit device for a liquid crystal display device, which generates a total of 8 or more voltage levels (V1, V2, ..., V7, V8; V1 < V2 < ... < V7 < V8), including ground voltage level V1, for applying the voltage of the difference signal of the scanning signal and data signal to a chiral nematic liquid crystal having at least two stable states, has means for generating maximum voltage level V8, means for generating potential difference V B , which becomes the reference for generating voltage levels V2 to V7, not including maximum voltage level V8 and ground voltage level V1, calculation means for calculating and outputting voltage levels V2 to V7 based on said potential difference V B , and changing means for changing the value of said potential difference V B from outside, whereby it becomes possible to adjust each voltage level (V2, ..., V7), except said ground voltage level V1 and maximum voltage level V8, simultaneously by changing said potential difference V B .

Claim 23

Power supply circuit device for a liquid crystal display device of claim 22 wherein the means that generates said potential difference V B generates said potential difference V B based on said maximum voltage level V8.

Claim 24

Power supply circuit device for a liquid crystal display device of claim 22 or 23 wherein said calculation means has a plurality of calculation circuits to which said voltage level V B is input and that calculate and output each of the voltage levels (V2, V3, V4) from among the plurality of levels (V1, V2, V3, V4), except said ground voltage level V1, of the first group on the low-voltage side of said eight or more voltage levels, and a plurality of subtraction circuits that generate each of the voltage levels (V5, V6, V7) of the voltage levels (V5, V6, V7, V8), except maximum voltage level V8, of the second group on the high voltage side by subtracting the respective outputs (V2, V3, V4) of said amplification means from said maximum voltage level V8.

Claim 25

Power supply circuit device for a liquid crystal display device of claims 19 to 24 wherein said potential difference level V B is set to V B = |Von - Voff|/2 determined from Von and Voff of said data signal.

Claim 26

Liquid crystal display device comprising liquid crystal panel made up of chiral nematic liquid crystal having at least two stable states and infused between a first substrate whereon are formed a plurality of scanning electrodes and a second substrate whereon are formed a plurality of data electrodes, power supply circuit that generates an even number of a total of 8 or more voltage levels (V1, V2, ..., V k/2 , ...,V k-1 , V k ; V1 < V2 < ...< V k/2 < ... < V k-1 < V k ), including ground voltage level V1, drive circuit to which is input said voltage levels from said power supply circuit and drives said liquid crystal by outputting a scanning signal to said scanning electrodes and outputting a data signal to said data electrodes of said liquid crystal panel, wherein said drive circuit comprises means for generating maximum voltage level V k , means for generating potential difference V B , which becomes the reference for generating voltage levels V2 to V k-1 , except maximum voltage level V k and ground voltage level V1, calculation means that calculates voltage levels V2 to V k-1 based on said potential difference V B , and changing means for changing the value of said potential difference V B from outside, whereby it becomes possible to adjust each voltage level (V2, ..., V k-1 ), except said ground voltage level V1 and maximum voltage level V k , simultaneously by changing said potential difference V B .

Claim 27

Power supply circuit device of a liquid crystal display device, which generates a total of 8 or more voltage levels (V1, V2, ..., V k/2 , ..., V k-1 , V k ; V1 < V2 < ...< V k/2 < ... < V k-1 < V k ), including ground voltage level V1, for applying the voltage of the difference signal of the scanning signal and the data signal to the liquid crystal, has means for generating maximum voltage level V k , (k - 1) resistors (R1, R2, ..., R k-1 ) connected in order from one end and in series to a path whose voltage at one end is said maximum voltage level V k and voltage at the other end is ground voltage level V1, (k - 2) voltage output terminals each connected between two adjacent resistors and that output said voltage levels V k-2 to V2 obtained by sequentially dropping the voltage via said resistors (R1, R2, ..., R k-1 ), and means for changing the resistance value of one of said (k - 1) resistors from outside, whereby it becomes possible to adjust each voltage level (V2 to V k-1 ), except said ground voltage level V1 and maximum voltage level V k , simultaneously by changing said resistance value.

Claim 28

Power supply circuit device of a liquid crystal display device, which generates a total of 8 voltage levels (V1, V2, ..., V7, V8; V1 < V2 < ... < V7 < V8), including ground voltage level V1, for applying the voltage of the difference signal of the scanning signal and data signal to a chiral nematic liquid crystal having at least two stable states, has means for generating maximum voltage level V8, seven resistors (R1, R2, ..., R7) connected in order from one end and in series to a path whose voltage at one end is said maximum voltage level V8 and voltage at the other end is the ground voltage level V1, six voltage output terminals each connected between two adjacent resistors and that output said voltage levels V7 to V2 obtained by sequentially dropping the voltage via said resistors (R1, R2, ..., R7), and means for changing the resistance value of said resistor R4 between said voltage output terminal of V5 and said voltage output terminal of V4 from outside, whereby it becomes possible to adjust each voltage level (V2 to V7), except said ground voltage level V1 and maximum voltage level V8, simultaneously by changing the resistance value of said resistor R4.

Claim 29

Liquid crystal display device having liquid crystal panel comprising chiral nematic liquid crystal having at least two stable states and infused between a first substrate whereon are formed a plurality of scanning electrodes and a second substrate whereon are formed a plurality of data electrodes, power supply circuit that generates an even number of a total of 8 or more voltage levels (V1, V2, ..., V k/2 , ...,V k-1 , V k ; V1 < V2 < ...< V k/2 < ... < V k-1 < V k ), including ground voltage level V1, drive circuit to which is input said voltage levels from said power supply circuit and drives said liquid crystal by outputting a scanning signal to said scanning electrodes and outputting a data signal to said data electrodes of said liquid crystal panel, wherein said drive circuit comprises means for generating the maximum voltage level V k , (k - 1) resistors (R1, R2, ..., R k-1 ) connected in order from one end and in series to a path whose voltage at one end is said maximum voltage level V k and voltage at the other end is ground voltage level V1, (k - 2) voltage output terminals each connected between two adjacent resistors and output said voltage levels V k-2 to V2 obtained by sequentially dropping the voltage via said resistors (R1, R2, ..., R k-1 ), and means for changing the resistance value of one of said (k - 1) resistors from outside, whereby it becomes possible to adjust each voltage level (V2 to V k-1 ), except said ground voltage level V1 and maximum voltage level V k , simultaneously by changing said resistance value.