Liquid crystal optical printing apparatus

Claim 2

A liquid crystal optical printing apparatus comprising a light source (k), a liquid crystal panel (a) which is arranged to be irradiated with light which is emitted from said light source (k) and which is provided with a plurality of light valves (a-1), and means (b) for selectively opening and closing said light valves (a-1) characterised in that the liquid crystal panel (a) is provided with nematic liquid crystal material whose dielectric anisotropy can be inverted in dependence upon the frequency, the driver means (b) being arranged to drive said liquid crystal panel (a) at higher and lower frequencies respectively to control the orientation of the molecules of the liquid crystal material so as to control the transmission and blocking of light through the liquid crystal panel (a).

Claim 3

A liquid crystal optical printing apparatus as claimed in claim 1 characterised by optical fibres (m-1) which are arranged to effect self-focussing of incident light passing through the light valves (a-1).

Claim 4

A liquid crystal optical printing apparatus as claimed in claim 1 or 2 characterised by a light shield (o) having a light outlet for shielding the liquid crystal panel (a) from light and/or heat transmitted from said light source (k) otherwise than through the light outlet, the driver means (b) being disposed externally of said light shield (o).

Claim 5

A liquid crystal optical printing apparatus according to any preceding claim characterised by a feedback system comprising a light source heater (s) for heating air; a motor fan (r) for supplying air heated by said light source heater (s) to heat said light source (k): a temperature sensor (t) for sensing the temperature of a part of said light source (k); and a temperature controller (u)-connected to said light source heater (s), said motor fan (r), and said temperature sensor (t) for maintaining the said part of said light source (k)at a substantially constant temperature.

Claim 6

A liquid crystal optical printing apparatus according to claim 4 characterised in that the temperature controller (u) is arranged to control the temperature of the wall of the light source (k) to be in the range of from 35 0 C to 45 ° C .

Claim 7

A liquid crystal optical printing apparatus according to any preceding claim characterised by a feedback system comprising a brightness sensor (q) for detecting the brightness of said light source (k), a drive unit (p) for driving said light source (k) and a brightness sensor controller (v) connected to said brightness sensor and to said drive unit (p).

Claim 8

A liquid crystal optical printing apparatus according to any preceding claim characterised in that said light source (k) has a reflective layer (k-3) except in a light emitting area (k-2), and a layer (k-4) of fluorescent material deposited on an inner surface of said reflective layer (k-3).

Claim 9

A liquid crystal optical printing apparatus according to any preceding claim including a feedback system comprising a panel heater (f) attached to said liquid crystal panel (a) for heating the latter, a sensor (h) for detecting the temperature of said liquid crystal panel (a), and a heater controller (g) connected to said panel heater (f) and the last-mentioned sensor (h).

Claim 10

A liquid crystal optical printing apparatus according to claim 8 characterised in that said panel heater (f) comprises a support body (f-3) and a resistive layer (f-2) deposited on said support body (f-3) for heating said liquid crystal panel (a) with Joule heat generated by said resistive layer (f-2).

Claim 11

A liquid crystal optical printing apparatus according to claim 2 characterised in that said fibres (m-1) are joined into a unitary array (m).

Claim 12

A liquid crystal optical printing apparatus according to any preceding claim characterised by a driver substrate (d) for driving said liquid crystal panel (a), and a flexible substrate (x), said driver substrate (d) and said liquid crystal panel (a) being interconnected by soldering through said flexible substrate (x).

Claim 13

A liquid crystal optical printing apparatus according to claim 11 characterised in that there are soldered junctions (z-52) between said flexible substrate and said liquid crystal panel, and between said flexible substrate (x) and said driver substrate (d), at least one of which soldered junctions (z-52) is reinforced with a reinforcing agent (z-51).

Claim 14

A liquid crystal optical printing apparatus according to claim 11 or 12 characterised in that said junctions are soldered thermally under pressure.

Claim 15

A liquid crystal optical printing apparatus according to any of claims 11-13 characterised in that at least said driver substrate (d) is covered with a moisture-resistant coating.

Claim 16

A liquid crystal optical printing apparatus as claimed in any preceding claim characterised by a rod lens (y) disposed between said light source (k) and said liquid crystal panel (a) for focusing light from said light source onto the liquid crystal panel (a).

Claim 17

A liquid crystal optical printing apparatus as claimed in any preceding claim characterised in that the liquid crystal panel (a) is composed of a pair of substrates (a-3, a-4) and a liquid crystal material (a-2) sealed between said substrates (a-3, a-4), said liquid crystal material (a-2) being of a nematic structure having a dielectric anisotropy which becomes zero at a crossover frequency, said liquid crystal material (a-2) having molecules disposed at wall surfaces of said substrates (a-3, a-4) and oriented parallel to the substrates, said liquid crystal molecules being twisted between said substrates, and polarizers disposed on opposite sides respectively of said liquid crystal panel (a), said liquid crystal material (a-2) being arrange d to be subjected to an applied electric field having a drive frequency lower than said crossover frequency and an applied electric field having a drive frequency higher than said crossover frequency to control orientation of the liquid crystal molecules for transmitting and blocking light through said liquid crystal panel (a).

Claim 18

A liquid crystal optical printing apparatus as claimed in claim 16 characterised in that the dielectric anisotropy is positive at a drive frequency lower than said crossover frequency, and is negative at a drive frequency higher than said crossover frequency.

Claim 19

A liquid crystal optical printing apparatus as claimed in claim 16 or 17 characterised in that the liquid crystal molecules are twisted through substantially 450° between said substrates (a-3, a-4).

Claim 20

A liquid crystal optical printing apparatus according to any of claims 16-18 characterised in that said liquid crystal panel (a) includes a liquid crystal sealing portion having layers (a-11) of Si0 2 on said substrates (a-3, a-4), a transparent electrode layer (a-12, a-13) on each of said layers (a-11) of SiO 2 , a metal layer (a-14) deposited on said transparent electrode layers (a-12, a-13) and extending from a terminal portion of said liquid crystal panel (a) to a position adjacent to a light valve, a layer (a-16) of Si0 2 deposited on said metal layer (a-14), a layer (a-17) of orienting agent deposited on said last-mentioned layer (a-16) of SiO 2 , said liquid crystal panel also including a terminal portion having a layer Si0 2 on each of said substrates, and a metal layer deposited on said last-mentioned layer of Si0 2 .

Claim 21

A liquid crystal optical printing apparatus according to any of claims 16-19 characterised in that said transparent electrode layers (a-12, a-13) include signal transparent electrodes (a-13) and scanning transparent electrodes (a-12) said signal transparent electrodes (a-13) having metal layers (a-14) extending from the terminal portion to the portion adjacent to the light valves (a-1) , and said scanning transparent electrodes (a-12) having metal layers (a-14) deposited except for the light valves (a-1).

Claim 22

A liquid crystal optical printing apparatus according to any of claims 16-20 characterised in that said polarizers have axes of polarization extending at substantially 90 0 to each other, said liquid crystal molecules being orientable perpendicularly to said substrates when said liquid crystal panel (a) is driven at a frequency to block light, and orientable parallel to said substrates when said liquid crystal panel (a) is driven at a frequency to transmit light.

Claim 23

A liquid crystal optical printing apparatus according to any preceding claim characterised in that said liquid crystal panel (a) is drivable by a liquid crystal drive waveform applied to scanning electrodes, said liquid crystal drive waveform having a period including a selected interval and a nonselected interval.

Claim 24

A liquid crystal optical printing apparatus according to claim 16 and claim 22 characterised in that a frequency higher than said crossover frequency is applied during said selected interval and a frequency lower than said crossover frequency is applied during said nonselected interval.

Claim 25

A liquid crystal optical printing apparatus according to claim 22 or 23 characterised in that said liquid crystal panel (a) is. drivable in a multiplex mode at a frequency having a period divided into n equal portions from the selected interval for the first scanning electrode to the selected interval for the nth scanning electrode, said selected interval being divided into selected and nonselected portions.

Claim 26

A liquid crystal optical printing apparatus according to claim 24 characterised in that n is 2.

Claim 27

A liquid crystal optical printing apparatus according to any of claims 1-21 characterised in that said liquid crystal panel is drivable by a liquid crystal drive waveform applied to scanning electrodes and having a first voltage amplitude and by a liquid crystal drive waveform applied to signal electrodes and having a second voltage amplitude, said first and second voltage amplitudes being equal to each other.

Claim 28

A liquid crystal optical printing apparatus according to any of claims 16-26 characterised in that said liquid crystal molecules are orientable parallel to said substrates (a-3, a-4) when a high-frequency voltage in the range of from +Vo to -Vo (Vo O) is applied to the liquid crystal panel (a) with a desired potential being a reference, and said liquid crystal molecules are orientable perpendicularly to said substrates (a-3, a-4) when a low-frequency voltage in the range of from +Vo to -Vo, or a high-frequency voltage in the range of from +2Vo to 0 or from o to -2Vo, is applied to said liquid crystal panel (a).

Claim 29

A liquid crystal optical printing apparatus according to claim 27 characterised in that light is allowed to pass through said liquid crystal panel (a) when said liquid crystal molecules are oriented parallel to said substrates (a-3, a-4), light being prevented from passing through said liquid crystal panel (a) when said liquid crystal molecules are oriented perpendicularly to said substrates (a-3, a-4)

Claim 30

A liquid crystal optical printing apparatus comprising a light source (k), a liquid crystal panel (a) which is arranged to be irradiated with light which is emitted from said light source (k) and which is provided with a plurality of light valves (a-1), means (b) for selectively opening and closing said light valves (a-1) , and a light shield (o) having a light outlet for shielding the liquid crystal panel (a) from light and/or heat transmitted from said light source (k) otherwise than through the light outlet characterised in that the means for selectively opening and closing the light valves (a-1) comprises driver means (b) disposed externally of said light shield (o), optical fibres (m-1) being employed to effect self-focusing of incident light passing through the light valves (a-1); the light source (k), light outlet, liquid crystal panel (a) and optical fibres (m-1) being arranged in a rectilineal arrangement.

Claim 31

A liquid crystal optical printing apparatus comprising a light source (k), a liquid crystal panel (a) which is arranged to be irradiated with light which is emitted from said light source (k) and which is provided with a plurality of light valves (a-1), means (b) for selectively opening and closing said light valves (a-1) , and a light shield (o) having a light outlet for shielding the liquid crystal panel (a) from light and/or heat transmitted from said light source (k) otherwise than through the light outlet characterised in that the means for selectively opening and closing the light valves (a-1) comprises driver means (b) disposed externally of said light shield (o), optical fibres (m-1) being employed to effect self-focusing of incident light passing through the light valves (a-1); the light source (k), light outlet, liquid crystal panel (a) and optical fibres (m-1) being arranged in a rectilineal arrangement.

Claim 32

A liquid crystal optical printing apparatus comprising a liquid crystal cell composed of a pair of substrates and a liquid crystal material sealed between said substrates, said liquid crystal material being of a nematic structure having a dielectric anisotropy which becomes zero at a crossover frequency, is positive at a drive frequency lower than said crossover frequency, and is negative at a drive frequency higher than said crossover frequency, said liquid crystal material having molecules disposed at wall surfaces of said substrates and oriented parallel to the substrates, said liquid crystal molecules being twisted through 450 between said substrates by being oriented and by an optically active agent added to said liquid crystal material, and polarizers disposed upwardly and downwardly of said liquid crystal cell, said liquid crystal material being subjected to an applied electric field having said drive frequency lower than said crossover frequency and an applied electric field having a drive frequency higher than said crossover frequency to control orientation of the liquid crystal molecules for transmitting and blocking light through said liquid crystal cell.

Claim 33

A liquid crystal optical printing apparatus comprising a liquid crystal cell composed of a pair of substrates and a liquid crystal material sealed between said substrates, said liquid crystal material being of a nematic structure having a dielectric anisotropy which becomes zero at a crossover frequency, is positive at a drive frequency lower than said crossover frequency, and is negative at a drive frequency higher than said crossover frequency, said liquid crystal material having molecules disposed at wall surfaces of said substrates and oriented parallel to the substrates, said liquid crystal molecules being twisted through 450 between said substrates by being oriented and by an optically active agent added to said liquid crystal material, and polarizers disposed upwardly and downwardly of said liquid crystal cell, said liquid crystal material being subjected to an applied electric field having said drive frequency lower than said crossover frequency and an applied electric field having a drive frequency higher than said crossover frequency to control orientation of the liquid crystal molecules for transmitting and blocking light through said liquid crystal cell.