US5548303A — Method of driving optical modulation device

Claim 1

Independent Claim 252 words

An optical modulation apparatus having a matrix electrode arrangement comprising a group of scanning electrodes, and a group of signal electrodes oppositely spaced from the group of scanning electrodes, wherein scanning signals are selectively applied sequentially and periodically to said group of scanning electrodes and information signals are selectively applied to said group of signal electrodes in synchronism with said scanning signals, thereby to effect optical modulation of an optical modulation material showing a first stable state and a second stable state with respect to an electric field applied thereto interposed between said groups of scanning electrodes and signal electrodes; the improvement wherein before or after an information signal is applied to a selected signal electrode among the group of signal electrodes in synchronism with a scanning signal applied to a selected scanning electrode among the group of scanning electrodes, an auxiliary signal different from the information signal is applied to the selected signal electrode in synchronism with the scanning signal, and an amplitude of a writing voltage applied to an intersection of the selected scanning electrode and the selected signal electrode is two or more times that of a first non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said first non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal, and a voltage applied to the non-selected scanning electrode.

Claim 2

Dependent Claim 252 words

An optical modulation apparatus having a matrix electrode arrangement comprising a group of scanning electrodes, and a group of signal electrodes oppositely spaced from the group of scanning electrodes, wherein scanning signals are selectively applied sequentially and periodically to said group of scanning electrodes and information signals are selectively applied to said group of signal electrodes in synchronism with said scanning signals, thereby to effect optical modulation of an optical modulation material showing a first stable state and a second stable state with respect to an electric field applied thereto interposed between said groups of scanning electrodes and signal electrodes; the improvement wherein before or after an information signal is applied to a selected signal electrode among the group of signal electrodes in synchronism with a scanning signal applied to a selected scanning electrode among the group of scanning electrodes, an auxiliary signal different from the information signal is applied to the selected signal electrode in synchronism with the scanning signal, and an amplitude of a writing voltage applied to an intersection of the selected scanning electrode and the selected signal electrode is two or more times that of a first non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said first non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal, and a voltage applied to the non-selected scanning electrode.

Claim 3

Dependent Claim 23 words

An optical modulation apparatus according to claim 1, wherein the scanning signal applied to the selected scanning electrode has phases of different voltages.

Claim 4

Dependent Claim 24 words

An optical modulation apparatus according to claim 2, wherein the scanning signal applied to the selected scanning electrode has phases of different voltage polarities.

Claim 5

Dependent Claim 34 words

An optical modulation apparatus according to claim 1, wherein the information signal applied to the selected signal electrode has a voltage different from that of a voltage signal applied to a non-selected signal electrode.

Claim 6

Dependent Claim 35 words

An optical modulation apparatus according to claim 4, wherein the information signal applied to the selected signal electrode has a voltage polarity different from that of the voltage signal applied to the non-selected signal electrode.

Claim 7

Dependent Claim 29 words

An optical modulation apparatus according to claim 1, wherein the auxiliary signal has a different voltage polarity from that of the information signal applied to the selected signal electrode.

Claim 8

Dependent Claim 18 words

An optical modulation apparatus according to claim 1, wherein said optical modulation material is a ferroelectric liquid crystal.

Claim 9

Dependent Claim 21 words

An optical modulation apparatus according to claim 7, wherein said ferroelectric liquid crystal is a liquid crystal having a smectic phase.

Claim 10

Dependent Claim 20 words

An optical modulation apparatus according to claim 7, wherein said liquid crystal is a liquid crystal having a chiral-smectic phase.

Claim 11

Dependent Claim 27 words

An optical modulation apparatus according to claim 9, wherein said liquid crystal having the chiral-smectic phase is in a state where a helical structure is not formed.

Claim 12

Dependent Claim 21 words

An optical modulation apparatus according to claim 10, wherein said liquid crystal having the chiral-smectic phase has a C-phase or H-phase.

Claim 13

Dependent Claim 21 words

An optical modulation apparatus according to claim 9, wherein said liquid crystal having the chiral-smectic phase has a C-phase or H-phase.

Claim 14

Independent Claim 254 words

A method of addressing a matrix array type liquid crystal display device with a chiral smectic liquid crystal layer whose pixels are defined by areas of overlay between a group of scanning electrodes on one side of the liquid crystal layer and a group of signal electrodes on the other side of the layer, and said pixels exhibit optical properties when selectively operated to fully ON and fully OFF states, wherein strobing pulses are applied serially to the group of scanning electrodes while data pulses are applied in parallel to the signal electrodes set in order to address the device line by line, wherein a waveform of each data pulse is balanced, bipolar and at least twice the duration of each strobing pulse, and wherein the data pulses, when applied to a non-addressed pixel in an original condition other than a fully ON state or fully OFF state, restore such non-addressed pixel to the original condition at the end of the data pulses, wherein an amplitude of a writing voltage applied to an intersection of a selected scanning electrode and a selected signal electrode is two or more times that of a scanning non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said scanning non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal and a voltage applied to the non-selected scanning electrode.

Claim 15

Independent Claim 254 words

A method of addressing a matrix array type liquid crystal display device with a chiral smectic liquid crystal layer whose pixels are defined by areas of overlay between a group of scanning electrodes on one side of the liquid crystal layer and a group of signal electrodes on the other side of the layer, and said pixels exhibit optical properties when selectively operated to fully ON and fully OFF states, wherein strobing pulses are applied serially to the group of scanning electrodes while data pulses are applied in parallel to the signal electrodes set in order to address the device line by line, wherein a waveform of each data pulse is balanced, bipolar and at least twice the duration of each strobing pulse, and wherein the data pulses, when applied to a non-addressed pixel in an original condition other than a fully ON state or fully OFF state, restore such non-addressed pixel to the original condition at the end of the data pulses, wherein an amplitude of a writing voltage applied to an intersection of a selected scanning electrode and a selected signal electrode is two or more times that of a scanning non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said scanning non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal and a voltage applied to the non-selected scanning electrode.

Claim 16

Dependent Claim 21 words

A method as claimed in claim 13, wherein the duration of each data pulse is twice that of each strobing pulse.

Claim 17

Dependent Claim 58 words

A method as claimed in claim 14, wherein each bipolar data pulse is one of positive and negative in a first half of the pulse duration and the other of negative and positive in a second half, and wherein the strobing pulses are unidirectional and synchronized with one of the first and second halves of the data pulses.

Claim 18

Dependent Claim 119 words

A method as claimed in claim 15, wherein prior to the addressing of the pixels associated with a group of the scanning electrodes, said pixels associated with said group of the scanning electrodes are all erased by a blanking pulse applied to said group of the scanning electrodes, which blanking pulse is of opposite polarity to the strobing pulses that after the blanking pulse induce a state change in the addressed pixels, and which is applied at or after commencement of the bipolar data pulses used to address the pixels associated with said group of the scanning electrodes to which the strobing pulse is applied immediately preceding application of the strobing pulse to said group of the scanning electrode.

Claim 19

Dependent Claim 18 words

A method as claimed in claim 14, wherein a waveform of each strobing pulse is balanced and bipolar.

Claim 20

Dependent Claim 91 words

A method as claimed in claim 17, wherein the waveform of each data pulse exhibits one polarity in a first half of the duration of the data pulse and the opposite polarity in a second half of the data pulse, and wherein the waveform of each strobing pulse is synchronized with the second half of the data pulse and exhibits a first polarity in a first half of the duration of the strobing pulse and a second polarity opposite to the first polarity in a second half of the strobing pulse.

Claim 21

Dependent Claim 91 words

A method as claimed in claim 17, wherein the waveform of each data pulse exhibits one polarity in a first half of the duration of the data pulse and the opposite polarity in a second half of the data pulse, and wherein the waveform of each strobing pulse is synchronized with the first half of the data pulse and exhibits a first polarity in a first half of the duration of the strobing pulse and a second polarity opposite to the first polarity in a second half of the strobing pulse.

Claim 22

Dependent Claim 58 words

A method as claimed in claim 13, wherein each bipolar data pulse is one of positive and negative in a first half of the pulse duration and the other of negative and positive in a second half, and wherein the strobing pulses are unidirectional and synchronized with one of the first and second halves of the data pulses.

Claim 23

Dependent Claim 119 words

A method as claimed in claim 20, wherein prior to the addressing of the pixels associated with the group of the scanning electrodes, said pixels associated with said group of the scanning electrodes are all erased by a blanking pulse applied to said group of the scanning electrodes, which blanking pulse is of opposite polarity to the strobing pulses that after the blanking pulse induce a state change in the addressed pixels, and which is applied at or after the commencement of the data pulses used to address the pixels associated with said group of the scanning electrodes to which the strobing pulse is applied immediately preceding application of the strobing pulse to said group of the scanning electrode.

Claim 24

Dependent Claim 18 words

A method as claimed in claim 13, wherein a waveform of each strobing pulse is balanced and bipolar.

Claim 25

Dependent Claim 91 words

A method as claimed in claim 22, wherein the waveform of each data pulse exhibits one polarity in a first half of the duration of the data pulse and the opposite polarity in a second half of the data pulse, and wherein the waveform of each strobing pulse is synchronized with the second half of the data pulse and exhibits a first polarity in a first half of the duration of the strobing pulse and a second polarity opposite to the first polarity in a second half of the strobing pulse.

Claim 26

Dependent Claim 78 words

A method as claimed in claim 22, wherein the waveform of each data pulse exhibits one polarity in a first half of the duration of the data pulse and the opposite polarity in a second half of the data pulse, and wherein the waveform of each strobing pulse is synchronized with the first half of the duration of the strobing pulse and a second polarity opposite to the first polarity in a second half of the strobing pulse.

Claim 27

Independent Claim 241 words

A method of addressing a matrix array type liquid crystal display device with a chiral smectic liquid crystal layer whose pixels are defined by areas of overlay between a group of scanning electrodes on one side of the liquid crystal layer and a group of signal electrodes on the other side of the layer, and said pixels exhibit optical properties when selectively operated to ON and OFF states, wherein strobing pulses are applied serially to the group of scanning electrodes while data pulses are applied in parallel to the group of the signal electrodes in order to address the device line by line, wherein a waveform of each data pulse is balanced, bipolar and at least twice the duration of a strobing pulse, and wherein the data pulses when applied to a non-addressed pixel retain such pixel in the ON or OFF state at the end of the data pulses, wherein an amplitude of a writing voltage applied to an intersection of the selected scanning electrode and a selected signal electrode is two or more times that of a first non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said first non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal and a voltage applied to the non-selected scanning electrode.

Claim 28

Independent Claim 241 words

A method of addressing a matrix array type liquid crystal display device with a chiral smectic liquid crystal layer whose pixels are defined by areas of overlay between a group of scanning electrodes on one side of the liquid crystal layer and a group of signal electrodes on the other side of the layer, and said pixels exhibit optical properties when selectively operated to ON and OFF states, wherein strobing pulses are applied serially to the group of scanning electrodes while data pulses are applied in parallel to the group of the signal electrodes in order to address the device line by line, wherein a waveform of each data pulse is balanced, bipolar and at least twice the duration of a strobing pulse, and wherein the data pulses when applied to a non-addressed pixel retain such pixel in the ON or OFF state at the end of the data pulses, wherein an amplitude of a writing voltage applied to an intersection of the selected scanning electrode and a selected signal electrode is two or more times that of a first non-writing voltage applied to an intersection of a non-selected scanning electrode and the selected signal electrode, the amplitudes of said writing voltage and said first non-writing voltage being respectively determined with respect to a reference voltage determined as a difference between a voltage applied to a signal electrode receiving no data signal and a voltage applied to the non-selected scanning electrode.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-08-20	2000-02-19	2000-08-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-08-20	2004-02-19	2004-08-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-08-20	2008-02-19	2008-08-20	$7700.00	Window Closed / Lapsed

Method of driving optical modulation device

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