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US 4,360,251 AGranted
Display device and method utilizing phase gratings
OwnerJan A. Rajchmaninventor
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OwnerJan A. Rajchmaninventor
Estimating the term…
An array of picture elements is disclosed for providing a display having selectivitely light or dark areas. The array includes light valves each comprising a pair of light transmissive elements having facing phase gratings, preferably sinusoidal, of like periodicity and parallel grating lines. The pair of elements are selectively positioned in two positions. In the first position, (the relatively dark transmissive position) the maxima and minima of one of the light transmissive elements are respectively coincident with the maxima and minima of the other light transmissive element. In the second position, (the relatively dark transmissive position) the maxima and minima of one of the light transmissive elements are respectively coincident with the minima and maxima of the other light transmissive element. Preferably the gratings comprise two sets of gratings having lines at right angles to each other, and at 45.degree. to the direction of motion which is used to position the two light transmissive elements from one selected position to the other. They alternatively may comprise three sets of lines at 60.degree.. The two selected positions may be defined by stops. Alternatively, the two positions may be defined by grating facing, complementary complex wave forms. One of the grating lines of one pair of light transmissive elements may be embossed from the other element of the same pair. The individual picture elements are defined by the intersections between rows and columns of the light transmissive elements. The rows employ piezoelectric elements, preferably using PVF.sub.2, to lock in place all the picture elements of the rows of the array except, when desired, a selected row, which is free to move, in order to change relative positions of the elements. The columns employ bimorphs, also preferably using PVF.sub.2.
A light valve comprising a pair of transparent sheets in close juxtaposition to each other, each sheet carrying on the side facing the other sheet two or more surface relief phase gratings, said gratings on each sheet being superimposed on each other with lines of any one grating making an angle to the lines of the others of the same sheet, and said gratings having like periodicity and identically oriented with the lines on one sheet being parallel to the lines of the other.
A light valve comprising two closely juxtaposed sheets each carrying on the side facing the other a surface relief phase grating pattern identical with the other of said patterns, and means for moving said sheets relative to one another in such a direction as to vary the total transmission of light through said light valve, and means to insure two definite relative positions of said sheets, one said position providing maximum light transmission and the other minimum light transmission.
A method for locking, into a chosen one of two well defined positions, a light valve element subject to sinusoidally oscillating motion in response to a restoring force at a point of near or zero velocity comprising the steps of releasing the element from the initial one or the other of said well defined positions and then subjecting the element to a locking force substantially at half period of said motion after said releasing.
A light valve comprising a pair of light transmissive elements each having a major face, said face of one element close to and facing the other major face, said faces respectively having phase gratings of like periodicity and each said face having grating lines parallel to the grating lines of the other said face of the pair, said elements being movable with respect to the other for selectively positioning said elements in one of two positions, in one of which positions the lines of one said face have their maxima and minima respectively coincident with the maxima and minima of the other said face, and in the other position the maxima and minima of one said face are coincident respectively with the minima and maxima of the other said face.
A method of providing a display of light and dark picture elements, said display comprising a plurality of pairs of light transmissive elements, each element of a pair having a major face close to and facing said major face of the other element of the same pair, said faces respectively having phase gratings of like periodicity and each face of a pair having grating lines parallel to the lines of the other face of the same pair, the steps of:
A display device comprising rows and columns defining at their intersections picture elements, each picture element comprising a pair of light transmissive elements, each element of a pair having a face with a phase grating close to and facing the face with the phase grating of the other element of the same pair and each face having grating lines of the same periodicity as and parallel to the grating lines of the other face of the same pair, and means for moving one of the elements of each pair with respect to the other for positioning the light transmissive elements of each pair selectively in either one of two positions, in one of said positions, the maxima and minima of the grating of the face of one of the pair coinciding respectively with the maxima and minima of the grating of the face of the other one of the same pair, and in the other one of said two positions the maxima and minima of the grating of the face of one of the pair coinciding respectively with the minima and maxima of the grating of the face of the other one of the same pair.
A method of operating a display device having horizontal and vertical lines defining at their intersections picture elements, each picture element comprising a pair of light transmissive elements, each element of a pair having a face with a phase grating close to and facing the face with the phase grating of the other light transmissive element of the same pair and each face having grating lines of the same periodicity as and parallel to the grating lines of the other face of the same pair, comprising the steps of:
Dependencies are inferred from the claim text.