Mos light valve with nematic liquid crystal operating in the surface mode

Claim 2

The light valve of claim 1, wherein the layer of liquid crystal is at least about 8 micrometers in thickness.

Claim 3

The light valve of claim 1, wherein the layer of liquid crystal is from about 8 to about 12 micrometers in thickness.

Claim 4

The light valve of claim 1, wherein the liquid crystal is sufficiently thick that the value of V p for the layer of liquid crystal is no less than V p *, a preselected voltage corresponding to a required response time.

Claim 5

The light valve of claim 1, wherein the dielectric layer is silicon dioxide, and the semiconductor layer is silicon.

Claim 6

A liquid crystal light valve, comprising: an active structure, comprising a layer of a nematic liquid crystal that is operable in a surface birefringent mode of operation, mirror means adjacent the liquid crystal layer for reflecting incident light directed against the mirror means through the liquid crystal, and a light valve substrate structure which is reactive to a write-in light beam, the substrate structure including a dielectric layer adjacent the mirror means and a semicoriductor body adjacent the dielectric layer; and means for applying an electric bias potential varying between a positive and a negative value across the active structure, the RMS potential producing a minimum in the transmittance of the liquid crystal to polarized light that is analyzed with a crossed analyzer, when there is no write-in light beam, the combination of thickness of the liquid crystal and the applied bias potential being such that the transmission as a function of time of the liquid crystal upon discontinuance of the write-in light beam exhibits an undershoot prior to approaching a steady state.

Claim 7

The light valve of claim 6, wherein the layer of liquid crystal is at least about 8 micrometers in thickness.

Claim 8

The light valve of claim 6, wherein the layer of liquid crystal is from about 8 to about 12 micrometers in thickness.

Claim 9

The light valve of claim 6, wherein the dielectric layer is silicon dioxide, and the semiconductor layer is silicon.

Claim 10

The light valve of claim 6, wherein the applied bias voltage is the greatest voltage that produces a minimum in the transmittance of the liquid crystal for the selected liquid crystal layer.

Claim 11

A liquid crystal light valve, comprising: an active structure, comprising a layer of a nematic liquid crystal that operates in a surface birefringent mode, mirror means adjacent the liquid crystal layer for reflecting incident light directed against the mirror means through the liquid crystal, and a light valve substrate structure including a dielectric layer adjacent the mirror means and a semiconductor body adjacent the dielectric layer which produces an electric current flow responsive to an incident write-in beam of light; and means for applying an alternating electric potential across the active structure, the electrical potential varying between positive and negative voltages and having an RMS bias voltage that is the highest voltage which produces an intensity minimum in the intensity-voltage curve of the liquid crystal without liquid crystal breakdown, in the absence of a write-in light beam.

Claim 12

A process for furnishing and operating a liquid crystal light valve, comprising the steps of: providing an active structure having a layer of a nematic liquid crystal that is operable in a surface birefringent mode when the liquid crystal is biased to its V p , a mirror adjacent the liquid crystal layer for reflecting a projected light beam directed against the mirror through the liquid crystal, and a light valve substrate structure including a dielectric layer adjacent the mirror and a semiconductor body adjacent the dielectric layer; and applying an alternating electric potential across the active structure, the electrical potential varying between a positive value and a negative value, and having an RMS voltage sufficient to bias the liquid crystal to its V p when no light is incident upon the light valve substrate structure.

Claim 13

The process of claim 12, including the additional step of directing a write-in light beam against the substrate structure.

Claim 14

The process of claim 12, wherein the layer of liquid crystal is at least about 8 micrometers in thickness.

Claim 15

The process of claim 12, wherein the layer of liquid crystal is from about 8 to about 12 micrometers in thickness.

Claim 16

The process of claim 12, wherein the thickness of the layer of liquid crystal is selected such that its V p is no less than V p *, a voltage corresponding to a preselected response time.

Claim 17

A process for controlling a projection light beam, comprising the steps of: providing a liquid crystal light valve with an active structure comprising a layer of a nematic liquid crystal that is operable in a surface birefringent mode of operation, mirror means adjacent the liquid crystal layer for reflecting incident light directed against the mirror means through the liquid crystal, and a light valve substrate structure which is reactive to a write-in light beam, the substrate structure including a dielectric layer adjacent the mirror means and a semiconductor body adjacent the dielectric layer; and applying across the active structure an electric bias potential varying between a positive and a negative value, the RMS potential producing a minimum in the transmittance of the liquid crystal to polarized light that is analyzed with a crossed analyzer, when there is no write-in light beam, the combination of thickness of the liquid crystal and the applied bias potential being such that the transmission as a function of time of the liquid crystal upon discontinuance of the write-in light beam exhibits an undershoot prior to approaching a steady state. directing a projection beam against the liquid crystal side of the active structure, while varying the write-in beam.

Claim 18

The process of claim 17, wherein the RMS potential of the bias voltage is at the V p of the liquid crystal.

Claim 19

The process of claim 17, wherein the thickness of the liquid crystal is from about 8 to about 12 micrometers.