Optically addressable spatial light modulator

Claim 2

A multi-pixel liquid crystal spatial light modulator having a plurality of picture elements, comprising; a pair of spaced transparent electrically conductive films, a photosensitive film carried by one of said conductive films, a plurality of conductive elements carried by said photosensitive film and arranged to define the position of each individual one of said plurality of modulator picture elements, each individual one of said conductive elements being electrically isolated from all other conductive elements, an apertured film carried by said photosensitive film substantially coplanar with said conductive elements, said apertured film having apertures formed therein and arranged in the form of the modulator picture elements, so as to define a plurality of areas of uncovered photosensitive film area, each of said uncovered areas of photosensitive film surrounding one of said conductive elements, liquid crystal activating voltage source means connected to said conductive films, chiral smectic liquid crystal means confined between said one conductive film and said photosensitive film, write beam means selectively directable to the side of said photosensitive film opposite from said plurality of conductive elements, whereby individual picture elements of said modulator are individually addressed by activating the portion of said photosensitive film that is associated with said addressed picture elements, thereby causing the corresponding conductive-element-defined chiral smectic liquid crystal picture elements to switch states, and read wavefront means directable to a side of said modulator.

Claim 3

The spatial light modulator of claim 1 wherein said liquid crystal means is a bistable ferroelectric liquid crystal means, and wherein said photosensitive film is constructed and arranged to define one of the group of photodiode and photoconductor.

Claim 4

The spatial light modulator of claim 1 wherein said conductive elements are formed in a geometric shape to minimize the area of diffraction of a light wavefront impinging upon such a shape, and wherein said apertures are of a similar geometric shape.

Claim 5

The spatial light modulator of claim 3 wherein said conductive elements are substantially round elements and said apertures are substantially round apertures.

Claim 6

The spatial light modulator of claim 1 wherein said apertured film is an opaque film, and including a masking member comprising a plurality of opaque areas corresponding to said plurality of areas of uncovered photosensitive film area, each of said opaque areas overlying one of said plurality of uncovered areas of photosensitive film.

Claim 7

The spatial light modulator of claim 5 wherein said masking member is mounted on the opposite side of said liquid crystal means from said photosensitive film.

Claim 8

The spatial light modulator of claim 6 wherein said liquid crystal means is a bistable ferroelectric liquid crystal means, and wherein said photosensitive film is constructed and arranged to define one of the group of photodiode and photoconductor.

Claim 9

The spatial light modulator of claim 7 wherein said conductive elements are substantially round opaque reflector elements, said apertures are substantially round apertures, and said opaque areas comprises substantially round opaque rings.

Claim 10

The spatial light modulator of claim 1 wherein said liquid crystal means is a bistable ferroelectric liquid crystal means, and wherein said apertured electrically film is an electrically conductive film, and including a source of potential adapted to drain charge from unswitched-state ferroelectric liquid crystal means picture element areas connected to said apertured conductive film.

Claim 11

The spatial light modulator of claim 9 wherein said photosensitive film is constructed and arranged to define one of the group of photodiode and photoconductor.

Claim 12

The spatial light modulator of claim 10 wherein said conductive elements are opaque reflector elements, said apertured film is an opaque film, and including a masking member comprising a plurality of opaque areas corresponding to said plurality of areas of uncovered photosensitive film area, each of said opaque areas overlying one of said plurality of uncovered areas of photosensitive film.

Claim 13

The spatial light modulator of claim 11 wherein said masking member is mounted on the opposite side of said ferroelectric liquid crystal means from said photosensitive film.

Claim 14

The spatial light modulator of claim 12 wherein said reflector elements are formed in a geometric shape to minimize the area of diffraction of a light wavefront impinging upon such said reflector elements, and wherein said apertures are of a similar geometric shape.

Claim 15

The spatial light modulator of claim 13 wherein said reflector elements are substantially round reflectors, said apertures are substantially round apertures, and said opaque areas comprises substantially round opaque rings.

Claim 16

The spatial light modulator of claim 1 including plate means for supporting said pair of spaced transparent electrically conductive films, said plate means being selected from the group glass, diamond or diamond-like film and boron nitride film.

Claim 17

The spatial light modulator of claim 15 wherein said a photosensitive film is an amorphous silicon photosensitve film.

Claim 18

The spatial light modulator of claim 16 wherein said amorphous silicon photosensitive film is configured from the groups p-i-n photodiode film and n-i-n photoconductor film.

Claim 21

The method of claim 18 including the steps of, providing said an apertured film as an electrically conductive film, and providing a source of bias potential connected to said apertured film, said source of bias potential being controllable to control the sensitivity threshold of said spatial light modulator pixel matrix.

Claim 22

The method of claim 18 including the step of providing ferroelectric liquid crystal means as said liquid crystal means.

Claim 23

The method of claim 18 including the step of providing amorphous silicon light-sensitive film as said light-sensitive film.

Claim 24

The method of claim 21 wherein said amorphous silicon light-sensitive film is constructed and arranged in accordance with the group of photodiode and photoconductor.

Claim 25

The method of claim 18 including the step of providing a masking layer on the opposite side of said liquid crystal means from said light-sensitive film, said masking layer providing an optical mask for the light-sensitive film areas that surround each of said conductive elements.

Claim 26

The method of claim 22 including the step of providing a pair of spaced light-transparent plate means for the support of said pair of light-transparent, conductive films.

Claim 27

The method of claim 24 wherein said plate means is selected from the group glass, diamond film, diamond-like film and boron nitride film.

Claim 28

The method of claim 25 including the step of providing ferroelectric liquid crystal means as said liquid crystal means.

Claim 29

The method of claim 26 including the step of providing amorphous silicon light-sensitive film as said light-sensitive film.

Claim 30

The method of claim 27 wherein said amorphous silicon light-sensitive film is constructed and arranged in accordance with the group of photodiode and photoconductor.

Claim 31

The method of claim 27 wherein said amorphous silicon light-sensitive film is constructed and arranged in accordance with the group p-i-n photodiode and n-i-n photoconductor.

Claim 32

The method of claim 18 including the steps of providing said an apertured film as an electrically conductive film, providing a masking layer on the opposite side of said liquid crystal means from said light-sensitive film, said masking layer providing an optical mask for the light-sensitive film areas that surround each of said conductive elements, and providing a source of bias potential connected to said apertured film, said source of bias potential operating to to drain charge from adjacent portions of said liquid crystal means.

Claim 33

The method of claim 30 including the step of adjusting the sensitivity threshold of said spatial light modulator by adjusting the magnitude of said source of bias potential.

Claim 34

The method of claim 31 including the step of providing a pair of spaced light-transparent plate means for the support of said pair of light-transparent and conductive films.

Claim 35

The method of claim 32 wherein said plate means is selected from the group glass, diamond film, diamond-like film and boron nitride film.

Claim 36

The method of claim 33 including the step of providing ferroelectric liquid crystal means as said liquid crystal means.

Claim 37

The method of claim 34 including the step of providing amorphous silicon light-sensitive film as said light-sensitive film.

Claim 38

The method of claim 35 wherein said amorphous silicon light-sensitive film is constructed and arranged in accordance with the group of photodiode and photoconductor.

Claim 39

The method of claim 35 wherein said amorphous silicon light-sensitive film is constructed and arranged in accordance with the group p-i-n photodiode and n-i-n photoconductor.

Claim 40

A reflection mode optically addressable spatial light modulator in the form of an array of pixel cells, comprising; ferroelectric liquid crystal film means, photosensitive film means, a plurality N of pixel cells, each cell of which is defined by one of a plurality N of electrically conductive reflectors, each reflector having one side thereof in physical contact with one side of said liquid crystal film means, and having the other side thereof in physical contact with one side of said photosensitive film means, opaque apertured film means having one side thereof in physical contact with said one side of said liquid crystal film means, and having the other side thereof in physical contact with said one side of said photosensitive film means, said apertured film means having a plurality N of small apertures positioned to coincide with said N reflectors, each reflector being spaced from its adjacent aperture so as to define an exposed annular area of said photosensitive film means surrounding each of said reflectors, a source of liquid crystal switching voltage connected between the other side of said liquid crystal film means and the other side of said photosensitive film means, write illumination means operable to selectively illuminate said other side of said photosensitive film means, individual pixel cells of said modulator being addressed by activating selected portions of said photosensitive film means using said write illumination means, the selected portions defining a data input to be stored in the modulator, the photosensitive film means when so activated operating to connect said source of switching voltage in a series circuit extending through said selected portions of said photosensitive film means and through the associated reflectors to the associated portions of said liquid crystal film means, and read illumination means for direction modulator reading illumination toward said other side of said liquid crystal film means.

Claim 41

A reflection mode optically addressable spatial light modulator in the form of an array of pixel cells, comprising; ferroelectric liquid crystal film means, photosensitive film means, a plurality N of pixel cells, each cell of which is defined by one of a plurality N of electrically conductive reflectors, each reflector having one side thereof in physical contact with one side of said liquid crystal film means, and having the other side thereof in physical contact with one side of said photosensitive film means, opaque apertured film means having one side thereof in physical contact with said one side of said liquid crystal film means, and having the other side thereof in physical contact with said one side of said photosensitive film means, said apertured film means having a plurality N of small apertures positioned to coincide with said N reflectors, each reflector being spaced from its adjacent aperture so as to define an exposed annular area of said photosensitive film means surrounding each of said reflectors, a source of liquid crystal switching voltage connected between the other side of said liquid crystal film means and the other side of said photosensitive film means, write illumination means operable to selectively illuminate said other side of said photosensitive film means, individual pixel cells of said modulator being addressed by activating selected portions of said photosensitive film means using said write illumination means, the selected portions defining a data input to be stored in the modulator, the photosensitive film means when so activated operating to connect said source of switching voltage in a series circuit extending through said selected portions of said photosensitive film means and through the associated reflectors to the associated portions of said liquid crystal film means, and read illumination means for direction modulator reading illumination toward said other side of said liquid crystal film means.

Claim 42

The light modulator of claim 38 wherein said photosensitive film means comprises photodiode film means, and said source of liquid crystal switching voltage operates to apply a first voltage polarity between said other side of said liquid crystal film means and said other side of said photodiode film means, to thereby erase all portions of said liquid crystal films means, and to subsequently apply a voltage of a second polarity between said other side of said liquid crystal film means and said other side of said photodiode film means, said write illumination means being operable during the period of application of said second polarity to store data in said modulator, and said read illumination means being operable thereafter to read data stored in said modulator.

Claim 43

The light modulator of claim 39 wherein said source of liquid crystal switching voltage includes a period of substantially zero potential, and wherein said read illumination means is operable to read data stored in said modulator during said period of substantially zero potential.

Claim 44

The light modulator of claim 39 wherein said apertured film means is electrically conductive, and wherein said other side of said liquid crystal film means and said apertured film means are both connected to the same electrical potential level.

Claim 45

The light modulator of claim 41 wherein said photodiode film means comprise amorphous silicon photodiode film means.

Claim 46

The light modulator of claim 42 including a plurality N of annular opaque members positioned to coincide with said N reflectors, said opaque elements being located adjacent said other side of said liquid crystal film means, and each of said opaque members overlying one of said exposed annular areas of said amorphous silicon photodiode film means surrounding each of said reflectors.

Claim 47

The light modulator of claim 38 wherein said photosensitive film means comprises a film photoconductor portion for each pixel cell of said modulator, wherein each pixel cell includes film resistor means having one end portion electrically connected to the reflector of its pixel cell, said film resistor means having a second end portion, wherein said source of liquid crystal switching voltage comprising a direct current source connected to apply a first voltage polarity to said other side of said photoconductor film means, and to apply a voltage of an opposite polarity to said second end portion of said resistor means, and means connecting said other side of said liquid crystal film means to a polarity intermediate said first and second polarity.

Claim 48

The light modulator of claim 44 wherein said source of liquid crystal switching voltage is of a variable magnitude, and means operable to vary the magnitude of said source in order to control the write illumination sensitivity threshold of said modulator.

Claim 49

The light modulator of claim 45 wherein said photoconductor portions comprise amorphous silicon photoconductor portion.

Claim 50

The light modulator of claim 46 including a plurality N of annular opaque members positioned to coincide with said N reflectors, said opaque element being located adjacent said other side of said liquid crystal film means, and each of said opaque members overlying one of said exposed annular areas of said photoconductor portion surrounding each of said reflectors.

Claim 51

A transmission mode optically addressable spatial light modulator in the form of an array of pixel cells, comprising; ferroelectric liquid crystal film means, photosensitive film means, a plurality N of pixel cells, each cell of which is defined by one of a plurality N of electrically conductive transparent elements, each transparent element having one side thereof in physical contact with one side of said liquid crystal film means, and having the other side thereof in physical contact with one side of said photosensitive film means, apertured film means having one side thereof in physical contact with said one side of said liquid crystal film means, and having the other side thereof in physical contact with said one side of said photosensitive film means, said apertured film means having a plurality N of small apertures positioned to coincide with said N transparent elements, each transparent element being spaced from its adjacent aperture so as to define an exposed annular area of said photosensitive film means surrounding each of said transparent elements, a source of liquid crystal switching voltage connected between the other side of said liquid crystal film means and the other side of said photosensitive film means, write illumination means operable to selectively illuminate said other side of said photosensitive film means, individual pixel cells of said modulator being addressed by activating selected portions of said photosensitive film means using said write illumination means, the selected portions defining a data input to be stored in the modulator, the photosensitive film means when so activated operating to connect said source of switching voltage in a series circuit extending through said selected portions of said photosensitive film means and through the associated conductive elements to the associated portions of said liquid crystal film means, and read illumination means for direction modulator reading illumination toward said liquid crystal film means.

Claim 52

A transmission mode optically addressable spatial light modulator in the form of an array of pixel cells, comprising; ferroelectric liquid crystal film means, photosensitive film means, a plurality N of pixel cells, each cell of which is defined by one of a plurality N of electrically conductive transparent elements, each transparent element having one side thereof in physical contact with one side of said liquid crystal film means, and having the other side thereof in physical contact with one side of said photosensitive film means, apertured film means having one side thereof in physical contact with said one side of said liquid crystal film means, and having the other side thereof in physical contact with said one side of said photosensitive film means, said apertured film means having a plurality N of small apertures positioned to coincide with said N transparent elements, each transparent element being spaced from its adjacent aperture so as to define an exposed annular area of said photosensitive film means surrounding each of said transparent elements, a source of liquid crystal switching voltage connected between the other side of said liquid crystal film means and the other side of said photosensitive film means, write illumination means operable to selectively illuminate said other side of said photosensitive film means, individual pixel cells of said modulator being addressed by activating selected portions of said photosensitive film means using said write illumination means, the selected portions defining a data input to be stored in the modulator, the photosensitive film means when so activated operating to connect said source of switching voltage in a series circuit extending through said selected portions of said photosensitive film means and through the associated conductive elements to the associated portions of said liquid crystal film means, and read illumination means for direction modulator reading illumination toward said liquid crystal film means.

Claim 53

The light modulator of claim 48 wherein said photosensitive film means comprises photoconductor film means, and said source of liquid crystal switching voltage operates to apply a first voltage polarity between said other side of said liquid crystal film means and said other side of said photoconductor film means, to thereby erase all portions of said liquid crystal film means, and to subsequently apply a voltage of a second polarity between said other side of said liquid crystal film means and said other side of said photoconductor film means, said write illumination means being operable during the period of application of said second polarity to store data in said modulator, and said read illumination means being concurrently operable during the period of application of said second polarity to read data stored in said modulator.

Claim 54

The light modulator of claim 49 wherein said apertured film means is electrically conductive, and wherein said apertured film means is connected to a voltage source of variable magnitude, and means operable to vary the magnitude of said source in order to control the write illumination sensitivity threshold of said modulator.

Claim 55

The light modulator of claim 50 including a plurality N of annular opaque members positioned to coincide with said N conductive elements, said opaque elements being located adjacent said other side of said liquid crystal film means, and each of said opaque members overlying one of said exposed annular areas of said photoconductor film means surrounding each of said conductive elements.