Rockwell International Corporation

Rockwell Science Center, Inc.

Donald B Taber

Bruce Kevin Winker

William J Gunning, Iii

Ragini Saxena

Leonard G Hale

Paul H Kobrin

John P Eblen, Jr

James C Beedy

An assembly for restricting the angle of vision of an image emitted from an LCD screen comprising a linearly parallel arrangement of two polarizing films with at least two waveplates there between. The transmission planes of the polarizing films are at an angle, preferrably 90&deg; to each other. At least two parallel waveplates are positioned between, the polarizing films. Each waveplate has parallel transmitting regions alternating between birefringent and isotropic regions. The waveplates are positioned in a spaced apart relationship to each other such that substantially orthogonal light passing through the first polarizing screen and one of the birefringent or isotropic alternating transmitting regions of the first waveplate will pass through the other of the alternating striped transmitting regions of the second waveplate. Light so transmitted will then pass through the second polarizing film and be viewable. At least a portion of the horizontal components of non-orthogonal light incident on the waveplate assembly will not pass through the second polarizing film This assembly results in a angle of vision narrower than from the LCD screen.

Staggered waveplate LCD privacy screen

A normally white liquid crystal display includes polarizer and analyzer layers having perpendicular absorbing axes. A liquid crystal layer is disposed between the polarizer layer and the analyzer layer, with its director exhibiting an azimuthal twist through the layer. First and second electrodes are proximate to first and second major surfaces of the liquid crystal layer. A first negatively birefringent compensator layer, oriented with its optical axis substantially parallel to the average direction of the optical axis within a central, nominally homeotropic region of the liquid crystal layer in its driven state, is disposed between the polarizer layer and the liquid crystal layer. A second negatively birefringent compensator layer, with a birefringence substantially the same as the birefringence of the first compensator layer and oriented with its optical axis substantially parallel to the optical axis of the first compensator layer, is disposed between the analyzer layer and the liquid crystal layer.

Negative optical compensator tilted in respect to liquid crystal cell

A normally white super-twist nematic liquid crystal display is disclosed. Between a polarizer layer and an analyzer layer, the display includes a super-twist nematic liquid crystal cell having first and second substrates and a liquid crystal layer disposed between the first and second substrates. The display further includes at least one positively birefringent A-plate compensator layer disposed between the polarizer layer and the super-twist nematic liquid crystal cell and at least one positively birefringent A-plate compensator layer disposed between the analyzer layer and the super-twist nematic liquid crystal cell to reduce chromaticity shifts of the display at wide viewing angles and over temperature variations.

Film compensated normally white super-twist nematic liquid crystal

An optical device for transforming light and an associated liquid crystal display is disclosed. The device includes a layer of cholesteric material of the type which transmits light having a first circular helicity and reflects light having a second circular helicity. A quarter-wave plate positioned on a first side of the layer of cholesteric material converts the transmitted light having the first circular helicity into linearly polarized light. A compensator including a positively birefringent C-plate layer is disposed between the layer of cholesteric material and the quarter-wave plate. The compensator reduces undesirable phase effects in the transmitted light introduced by the layer of cholesteric material. The disclosed LCD employs the optical device to increase backlighting efficiency while improving field of view and chromaticity of the display.

Birefringent compensator for reflective polarizers

An optical O-plate compensation device, in accordance with the invention, uses an inorganic thin film which is grown by physical vapor deposition at oblique incidence. The resulting thin film exhibits a biaxial form birefringence and performs, in a liquid crystal display (LCD), in a similar manner to uniaxial films with its extraordinary axis oriented obliquely at about 45.degree. with respect to the surface of the film. The invention makes possible a significant improvement in the gray scale properties and contrast ratios of liquid crystal displays (LCDs) over a wide range of viewing angles.

Inorganic thin film compensator for improved gray scale performance in

An improved normally white super-twist nematic (OMI) liquid crystal display exhibits a dramatically improved horizontal viewing angle as compared to conventional OMI displays. The display's liquid crystal cell has a twist angle greater than about 180.degree. and less than about 270.degree., preferably between 220.degree. and 250.degree., and a phase retardation of between 500 nanometers (nm) and 850 nm. The improved display includes a novel compensator which incorporates, as one of its compensation elements, a positively birefringent oblique compensator layer (referred to as an O-plate compensator layer). Additionally, a positively birefringent A-plate compensator layer and one or more negatively birefringent C-plate compensator layers may be used in the display.

Optical compensator including an o-plate for super-twist nematic liquid

A liquid crystal display for viewing at various angles with respect to a normal axis perpendicular to the display includes a polarizer layer having an absorbing axis, an analyzer layer having an absorbing axis substantially perpendicular to the absorbing axis of the polarizer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer and having a director exhibiting an azimuthal twist through the layer with respect to the normal axis, a first electrode proximate to a first major surface of the liquid crystal layer, a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential, and a compensator, including a positively birefringent O-plate compensator layer disposed between the polarizer layer and the analyzer layer with its principal symmetry axis oriented at a substantially oblique angle with respect to the normal axis.

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Thousand Oaks, CA, United States of America

Donald B Taber