Liquid crystal optical device

Claim 2

In a liquid crystal optical device comprising at least one polarizer, and a cell structure including a pair of base plates having electrodes thereon and a ferroelectric liquid crystal disposed between the base plates, said cell structure having been subjected to a monoaxial orientation treatment; the improvement wherein: said ferroelectric liquid crystal is disposed in a layer thin enough to release its own helical structure, and said polarizer is arranged such that the angle between the polarizing direction of the polarizer and the axial direction of the monoaxial orientation treatment is smaller than the angle between the axial direction of the monoaxial treatment and an average molecular axis direction of the ferroelectric liquid crystal under application of a polarity of voltage between the electrodes.

Claim 3

The liquid crystal device according to claim 1, wherein the ferroelectric liquid crystal shows a cholesteric phase at a high temperature.

Claim 4

The liquid crystal device according to claim 1, which comprises a pair of polarizers sandwiching the cell structure and arranged in the form of cross nicols.

Claim 5

The liquid crystal device according to claim 1, wherein said monoaxial orientation treatment is a rubbing treatment.

Claim 6

The liquid crystal device according to claim 1, wherein said monoaxial orientation treatment is an oblique vapor deposition treatment.

Claim 7

The liquid crystal device according to claim 1, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.

Claim 8

The liquid crystal device according to claim 6, wherein said chiral smectic phase is chiral smectic C phase, chiral smectic G phase, chiral smectic F phase, chirasl smectic I phase, chiral smectic J phase, chiral smectic K phase, or chiral smectic H phase.

Claim 9

The liquid crystal device according to claim 6, wherein the ferroelectric liquid crystal is formed in a layer having a thickness smaller than the pitch of the helical structure thereof.

Claim 10

A liquid crystal optical device comprising a pair of base plates each provided with an electrode, a ferroelectric liquid crystal sealed between said pair of base plates, and at least one polarizer, wherein at least one of said base plates is provided with a monoaxial orientation axis, said ferroelectric liquid crystal gives an average molecular axis direction forming an angle ○H from the monoaxial orientation axis under application of a polarity of voltage, and said ferroelectric liquid crystal gives an average molecular axis direction forming an angle ○H from the monoaxial orientation axis under the application of zero-voltage, the angle ○H being smaller than H, and said polarizer is arranged such that the polarizing axis thereof is substantially parallel with the average molecular axis direction of the ferroelectric liquid crystal giving the angle ○H .

Claim 11

A liquid crystal optical device comprising a pair of base plates each provided with an electrode, a ferroelectric liquid crystal sealed between said pair of base plates, and at least one polarizer, wherein at least one of said base plates is provided with a monoaxial orientation axis, said ferroelectric liquid crystal gives an average molecular axis direction forming an angle ○H from the monoaxial orientation axis under application of a polarity of voltage, and said ferroelectric liquid crystal gives an average molecular axis direction forming an angle ○H from the monoaxial orientation axis under the application of zero-voltage, the angle ○H being smaller than H, and said polarizer is arranged such that the polarizing axis thereof is substantially parallel with the average molecular axis direction of the ferroelectric liquid crystal giving the angle ○H .

Claim 12

The device according to claim 9, wherein said monoaxial orientation treatment is a rubbing treatment.

Claim 13

The device according to claim 9, wherein said monoaxial treatment is an oblique vapor deposition treatment.

Claim 14

The device according to claim 9, wherein said angles ○H and θ satisfy the relationship of 1/10× ○H <θ.

Claim 15

The device according to claim 9, wherein said ferroelectric liquid crystal is in a smectic phase.

Claim 16

The device according to claim 13, wherein said smectic phase is a chiral smectic phase.

Claim 17

The device according to claim 4, wherein said chiral smectic phase is chiral smectic C phase, chiral smectic G phase, chiral smectic F phase, chiral smectic I phase, chiral smectic J phase, chiral smectic K phase or chiral smectic H phase.

Claim 18

The device according to claim 9, wherein said ferroelectric liquid crystal is formed in a layer having a thickness thinner than the pitch of the helical structure of the ferroelectric liquid crystal.

Claim 19

The device according to claim 9, wherein said ferroelectric liquid crystal shows a choelestric phase at a high temperature.

Claim 20

The device according to claim 9, wherein said at least one polarizer is provided in a pair sandwitching the pair of base plates and with their polarizing directions arranged in a cross nicol relationship.

Claim 21

The device according to claim 9, wherein said ferroelectric liquid crystal provides a different monoaxially anisotropic phase having an axial direction through phase transition thereof, and said monoaxial orientation axis is provided in a direction substantially parallel with the axis direction of said different monoaxially anisotropic phase.

Claim 22

The device according to claim 19, wherein said different monoaxially anisotropic phase is a smectic A phase.

Claim 23

A liquid crystal optical device comprising a plurality of picture elements arranged in a plurality of rows, which device is driven by applying a writing signal row by row to the picture elements and the written states of the picture elements in the row to which the writing signal has been applied are retained until a subsequent writing signal is applied to the row, wherein each of said plurality of picture elements is formed by a pair of opposite electrodes, a ferroelectric liquid crystal interposed between the opposite electrodes and at least one polarizer disposed on the side of one of the opposite electrodes opposite to the ferroelectric liquid crystal, said ferroelectric liquid crystal is disposed between a pair of base plates each having one of said pair of opposite electrodes, and at least one of said pair of base plates is provided with a monoaxial orientation axis, said ferroelectric liquid crystal having a first orientation state and a second orientation state with respect to an electric field applied thereto, said ferroelectric liquid crystal gives an average moelcular axis direction forming an angle ○H from the monoaxial orientation axis under application of a writing signal of a polarity of voltage, said ferroelectric liquid crystal further gives an average molecular axis direction forming an angle θ from the monoaxial orientation axis under the memory state after the application of the writing signal, the angle θ being smaller than ○H , and said one polarizer is arranged such that the polarizing axis thereof is substantially parallel with the average molecular axis direction of the ferroelectric liquid crystal giving the angle θ.

Claim 24

A liquid crystal optical device comprising a plurality of picture elements arranged in a plurality of rows, which device is driven by applying a writing signal row by row to the picture elements and the written states of the picture elements in the row to which the writing signal has been applied are retained until a subsequent writing signal is applied to the row, wherein each of said plurality of picture elements is formed by a pair of opposite electrodes, a ferroelectric liquid crystal interposed between the opposite electrodes and at least one polarizer disposed on the side of one of the opposite electrodes opposite to the ferroelectric liquid crystal, said ferroelectric liquid crystal is disposed between a pair of base plates each having one of said pair of opposite electrodes, and at least one of said pair of base plates is provided with a monoaxial orientation axis, said ferroelectric liquid crystal having a first orientation state and a second orientation state with respect to an electric field applied thereto, said ferroelectric liquid crystal gives an average moelcular axis direction forming an angle ○H from the monoaxial orientation axis under application of a writing signal of a polarity of voltage, said ferroelectric liquid crystal further gives an average molecular axis direction forming an angle θ from the monoaxial orientation axis under the memory state after the application of the writing signal, the angle θ being smaller than ○H , and said one polarizer is arranged such that the polarizing axis thereof is substantially parallel with the average molecular axis direction of the ferroelectric liquid crystal giving the angle θ.

Claim 25

The device according to claim 21, wherein said angles ○H and θsatisfy the relationship of 1/10× ○H <θ.

Claim 26

The device according to claim 21, wherein said writing signal applied to a row of picture element is a pulse signal having a pulse width in the range of 0.1 μsec to 2 msec.

Claim 27

The device according to claim 23, wherein said pulse signal is in the form of a rectangular wave, sine wave or triangular wave.

Claim 28

The device according to claim 21, wherein said writing signal applied to a row of picture elements has a voltage in the range of 3 to 70 volts.

Claim 29

The device according to claim 21, wherein the time period between said writing signal and said subsequent writing signal is equal to a period of one frame or one field.

Claim 30

The device according to claim 21, wherein a plurality of pairs of said opposite electrodes form a matrix electrode structure comprising a group of scanning electrodes and a group of signal electrodes intersecting with the scanning electrodes, each intersection of the scanning electrodes and the signal electrodes forming a picture element.

Claim 31

The device according to claim 21, wherein said at least one polarizer is provide in pair sandwiching the opposite electrodes and with their polarizing directions arranged in a cross nicol relationship.

Claim 32

The liquid crystal optical device according to claim 21, which is driven by the combination of a first phase of applying a first voltage signal for orienting the ferroelectric liquid crystal to the first stable orientation and a second phase of applying a second voltage signal for orienting the ferroelectric liquid crystal to the second stable orientation; said first and second voltage signals having mutually opposite polarities.

Claim 33

The device according to claim 21, wherein said ferroelectric liquid crystal provides a different monoaxially anisotropic phase having an axial direction through phase transition thereof, and said monoaxial orientation axis is provided in a direction substantially parallel with the axis direction of said different monoaxially anisotropic phase.