US4836656A — Driving method for optical modulation device

Claim 1

Independent Claim 253 words

A driving method for an optical modulation device comprising scanning electrodes, signal electrodes disposed intersecting the scanning electrodes so as to form a pixel at each intersection of the scanning electrodes and signal electrodes, and an optical modulation material disposed between the scanning electrodes and the signal electrodes and assuming different orientation states when supplied with voltage so different polarities exceeding threshold voltages; said driving method comprising a first phase, a second phase and a third phase, wherein said driving method comprises the steps of: sequentially applying voltages to all or prescribed pixels on a selected scanning electrode to write in said all or prescribed pixels in a writing period for the selected scanning electrode, the third phase in the writing period for the selected scanning electrode preceding the first phase in the writing period for a subsequently selected scanning electrode; applying to said all or prescribed pixels voltages of one polarity sufficient for causing the optical modulation material to assume a first orientation state in the first and second phases, said voltages of one polarity having different amplitudes in the first and second phases; and applying to a selected pixel a voltage of the other polarity sufficient causing the optical modulation material to assume a second orientation state in the third phase, and applying a voltage of the other polarity, not causing the optical modulation material to assume the second orientation state, to the other pixels, respectively of said all or prescribed pixels on the selected scanning electrode in the third phase.

Claim 2

Dependent Claim 253 words

A driving method for an optical modulation device comprising scanning electrodes, signal electrodes disposed intersecting the scanning electrodes so as to form a pixel at each intersection of the scanning electrodes and signal electrodes, and an optical modulation material disposed between the scanning electrodes and the signal electrodes and assuming different orientation states when supplied with voltage so different polarities exceeding threshold voltages; said driving method comprising a first phase, a second phase and a third phase, wherein said driving method comprises the steps of: sequentially applying voltages to all or prescribed pixels on a selected scanning electrode to write in said all or prescribed pixels in a writing period for the selected scanning electrode, the third phase in the writing period for the selected scanning electrode preceding the first phase in the writing period for a subsequently selected scanning electrode; applying to said all or prescribed pixels voltages of one polarity sufficient for causing the optical modulation material to assume a first orientation state in the first and second phases, said voltages of one polarity having different amplitudes in the first and second phases; and applying to a selected pixel a voltage of the other polarity sufficient causing the optical modulation material to assume a second orientation state in the third phase, and applying a voltage of the other polarity, not causing the optical modulation material to assume the second orientation state, to the other pixels, respectively of said all or prescribed pixels on the selected scanning electrode in the third phase.

Claim 3

Dependent Claim 38 words

A driving method according to claim 1, further comprising the step of applying a voltage, having an amplitude not exceeding the threshold voltages of the optical modulation material, to said all or prescribed pixels in the second phase.

Claim 4

Dependent Claim 78 words

A driving method according to claim 1, further comprising the step of applying a voltage to said selected scanning electrode of the same polarity in the first and second phases with respect to the potential of a nonselected scanning electrode, and wherein said same polarity is opposite to the polarity of said voltage applied to said all or prescribed pixels on the selected scanning electrode in the third phase with respect to the potential of the nonselected electrode.

Claim 5

Dependent Claim 56 words

A driving method according to claim 1, further comprising the step of continually applying a voltage of said same polarity of a pixel on a scanning electrode, wherein the maximum duration of the continually applied voltage of the same polarity applied to the pixel on the scanning electrode is twice the duration of the first phase.

Claim 6

Dependent Claim 62 words

A driving method according to claim 1, wherein said writing period for the selected scanning electrode further comprises a fourth phase before the first phase or after the third phase, and wherein said method further comprises the step of applying a voltage in the fourth phase, not exceeding the threshold voltages of the optical modulation material to said all or prescribed pixels.

Claim 7

Dependent Claim 35 words

A driving method according to claim 5, further comprising the step of applying a 0 voltage to the selected scanning electrode with respect to the potential of a nonselected scanning electrode in the fourth phase.

Claim 8

Dependent Claim 117 words

A driving method according to claim 1, wherein said writing period further comprises a fourth phase, wherein in said method further comprises the step of applying a voltage, not exceeding the threshold voltages of the optical modulation materials, to said all or prescribed pixels in the fourth phase, wherein the voltage applied to the selected scanning electrode in the first phase and a voltage applied to the selected scanning electrode in the third phase have opposite polarities with respect to the potential of a nonselected scanning electrode, and wherein the voltages applied to the selected scanning electrode in the second and fourth phases have a zero voltage with respect to the potential of the nonselected scanning electrode.

Claim 9

Dependent Claim 50 words

A driving method according to claim 7, wherein said first, second, third and fourth phases have durations of t 1 , t 2 , t 3 and t 4 , respectively, satisfying the relationships of t 1 =t 3 , t 2 =t 4 and 1/2·t 1 =t 2 .

Claim 10

Dependent Claim 75 words

A driving method according to claim 1, wherein the voltage applied to the selected scanning electrode in the first phase and the voltage applied to the selected scanning electrode in the third phase have opposite polarities with respect to the potential of a nonselected scanning electrode, and wherein the voltage applied to the selected scanning electrode in the second phase has a voltage of 0 with respect to the potential of a nonselected scanning electrode.

Claim 11

Dependent Claim 39 words

A driving method according to claim 1, further comprising the steps of: sequentially applying a scanning selection signal for defining a selected scanning electrode to the scanning electrodes; and cyclically repeating the sequential application of the scanning selection signal.

Claim 12

Dependent Claim 17 words

A driving method according to claim 1, wherein said optical modulation material comprises a ferroelectric liquid crystal.

Claim 13

Dependent Claim 18 words

A driving method according to claim 11, wherein said ferroelectric liquid crystal comprises a chiral smectic liquid crystal.

Claim 14

Dependent Claim 38 words

A driving method according to claim 12, wherein said chiral smectic liquid crystal is disposed in a layer thin enough to release the helical structure of the chiral smectic liquid crystal in the absence of an electric field.

Claim 15

Dependent Claim 41 words

A driving method according to claim 1, wherein the voltage of one polarity applied to the selected pixel in the second phase and the voltage of one polarity applied to the other pixels in the first phase have the same amplitude.

Claim 16

Dependent Claim 56 words

A driving method according to claim 14, further comprising the step of continually applying a voltage of said same polarity to a pixel on a scanning electrode, wherein the maximum duration of the continually applied voltage of the same polarity applied to the pixel on the scanning electrode is twice the duration of the first phase.

Claim 17

Dependent Claim 55 words

A driving method according to claim 14, further comprising the step of applying voltages to the pixels on a nonselected scanning electrode of the scanning electrodes of the same polarity in the first and third phases and applying voltages to the pixels on a nonselected scanning electrode of a polarity opposite to said same polarity.

Claim 18

Dependent Claim 60 words

A driving method according to claim 16, further comprising the step of applying a voltage to pixels on a nonselected scanning electrode, and applying a voltage to a pixel on a selected signal electrode of a polarity opposite to that of the voltage applied to the pixel on the nonselected signal electrode, respectively in the first, second and third phases.

Claim 19

Dependent Claim 42 words

An optical modulation method according to claim 1, wherein the voltage of one polarity applied to the selected pixel in the first phase and the voltage of one polarity applied to said other pixels in the first phase have the same amplitude.

Claim 20

Dependent Claim 261 words

An optical modulation apparatus comprising: an optical modulation device comprising scanning electrodes, signal electrodes disposed intersecting the scanning electrodes so as to form a pixel at each intersection of the scanning electrodes and signal electrodes, and an optical modulation material disposed between the scanning electrodes and signal electrodes and assuming different orientation states when supplied with voltages of different polarities exceeding threshold voltages; and a driving unit for driving the optical modulation device according to a method which comprises the steps of: sequentially applying voltages to all or prescribed pixels on a selected scanning electrode to write in said all or prescribe pixels of the selected scanning electrode in a writing period comprising first, second, and third phases, wherein the third phase in the writing period for the selected scanning electrode precedes the first phase in the writing period for a subsequently selected scanning electrode; applying voltages of one polarity to said all or prescribed pixels in the first and second phases which are sufficient for causing the optical modulation material to assume a first orientation state, said voltages of one polarity having different amplitudes in the first and second phases; applying a voltage of the other polarity in the third phase to a selected pixel which is sufficient for causing the optical modulation material to assume a second orientation state; and applying, in the third phase, a voltage of the other polarity, not causing the optical modulation material to assume the second orientation state, to the other pixels, respectively of said all or prescribed pixels on the selected scanning electrode.

Claim 21

Dependent Claim 261 words

An optical modulation apparatus comprising: an optical modulation device comprising scanning electrodes, signal electrodes disposed intersecting the scanning electrodes so as to form a pixel at each intersection of the scanning electrodes and signal electrodes, and an optical modulation material disposed between the scanning electrodes and signal electrodes and assuming different orientation states when supplied with voltages of different polarities exceeding threshold voltages; and a driving unit for driving the optical modulation device according to a method which comprises the steps of: sequentially applying voltages to all or prescribed pixels on a selected scanning electrode to write in said all or prescribe pixels of the selected scanning electrode in a writing period comprising first, second, and third phases, wherein the third phase in the writing period for the selected scanning electrode precedes the first phase in the writing period for a subsequently selected scanning electrode; applying voltages of one polarity to said all or prescribed pixels in the first and second phases which are sufficient for causing the optical modulation material to assume a first orientation state, said voltages of one polarity having different amplitudes in the first and second phases; applying a voltage of the other polarity in the third phase to a selected pixel which is sufficient for causing the optical modulation material to assume a second orientation state; and applying, in the third phase, a voltage of the other polarity, not causing the optical modulation material to assume the second orientation state, to the other pixels, respectively of said all or prescribed pixels on the selected scanning electrode.

Claim 22

Dependent Claim 18 words

An optical modulation apparatus according to claim 19, wherein said optical modulation material comprises a ferroelectric liquid crystal.

Claim 23

Dependent Claim 19 words

An optical modulation apparatus according to claim 20, wherein said ferroelectric liquid crystal comprises a chiral smectic liquid crystal.

Claim 24

Dependent Claim 39 words

An optical modulation apparatus according to claim 21, wherein said chiral smectic liquid crystal is disposed in a layer thin enough to release the helical structure of the chiral smectic liquid crystal in the absence of an electric field.

Claim 25

Dependent Claim 42 words

An optical modulation apparatus according to claim 19, wherein the voltage of one polarity applied to the selected pixel in the second phase and the voltage of one polarity applied to the other pixels in the first phase have the same amplitude.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-06-05	1992-12-05	1993-06-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-06-05	1996-12-05	1997-06-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-06-05	2000-12-05	2001-06-06	$7700.00	Window Closed / Lapsed

Driving method for optical modulation device

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