US 4,792,850 A · Method and system employing a push-pull liquid crystal modulator

Abstract

A system and method employing a push-pull modulator for stereoscopic image selection. The modulator includes a pair of surface mode liquid crystal cells having orthogonal rub axes, and a linear polarizer having absorption axis bisecting the orthogonal rub axes, and has high speed, good transmission, and symmetrical dynamic range characteristics. A field-sequential steroscopic video image may be transmitted from a video display screen (or video projector) through the modulator as the cells of the modulator are driven so that fields of alternately left-handed circularly polarized light and right-handed circularly polarized light will emerge. The transmitted circularly polarized light may be viewed using passive spectacles incorporating circular polarizing filters.

Claims31

Dependent claims

A push-pull liquid crystal modulator system, for transmitting circularly polarized light of alternating handedness,including:

(a) a pair of surface mode liquid crystal cells having orthogonal rub axes;
(b) a linear polarizer having an absorption axis bisecting the orthogonal rub axes;
and;
(c) a driver electrically coupled to the cells, and capable of driving the cells so that when one cell in the pair is in a higher voltage state, the other cell in the pair is in a lower voltage state.

1 more element

Stereoscopic video display apparatus, including:

(a) a monitor for displaying a field-sequential stereo image;
and
(b) a shutter system, including a push-pull liquid crystal modulator including a pair of surface mode liquid crystal cells having orthogonal rub axes and a linear polarizer having an absorption axis bisecting the orthogonal rub axes, and capable of sequentially transmitting left-hand circularly polarized light comprising the image and right-hand circularly polarized light comprising the image.

A method of displaying a stereoscopic video image, including the steps of:

displaying a field-sequential stereoscopic image whose fields alternate at a field rate;
positioning a push-pull liquid crystal modulator that includes a pair of surface mode liquid crystal cells with orthogonal rub axes and a linear polarizer having an absorption axis bisecting the orthogonal rub axes, so that light comprising the image will propagate therethrough;
and
driving the modulator in synchronization with the fields of the image so that the transmitted image emerging from the modulator consists of right-handed circularly polarized fields alternating at the field rate with left-handed circularly polarized fields.

1 more element

Dependencies are inferred from the claim text.

Method and system employing a push-pull liquid crystal modulator

Life of this patent

Method and system employing a push-pull liquid crystal modulator

Life of this patent

Abstract

Claims31