Display for head mounting
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorGöte Sigvard Svedenkrans
Life of this patent
Estimating the term…
Abstract
In order to visualize an active matrix liquid crystal image generator, it is illuminated in a prism system by a light source and a collimator directing light into the prism system and made linear polarized and reflected by a first half-mirror layer between two joined prism surfaces, the image generator differentially twisting pixelwise the polarization plane of reflected light therefrom, such that twisted light can traverse the first half-mirror layer and a second half-mirror layer for focusing by a concave mirrors, the second half-mirror then directing a virtual image toward an eye location, from which a natural scene may also be viewed. The prism system, as seen in a plan perpendicular to the viewing direction, includes two isosceles prisms and one of trapezium section, or preferably that of a parallelogram.
Claims4
A display for head mounting comprising a light reflecting type spatial light modulator, an illumination device for illuminating the said image generator and optical means for projecting an image generated by the image generator toward an exit pupil at an eye location for viewing by an eye together with an eventual natural scene in front of the eye emplacement;
- wherein said optical means comprises prisms forming two beam splitters, each beam splitter formed by the intersection of two prism surfaces, a first one of said beam splitters reflecting light from said illumination device to illuminate said image generator, a spherical mirror imaging said illuminated image generator by reflecting light from said image generator traversing said first beam splitter and a second beam splitter, said second beam splitter reflecting light reflected by said spherical mirror toward said eye location;
- and
- wherein said optical means comprises a first prism, a second prism and a third prism, first and third prisms having right isosceles triangular sections in a plane perpendicular to said beam splitters, the hypotenuses thereof forming each one surface in each of said beam splitter layers, and the second prism having in the said plane a trapezium section.
Dependencies are inferred from the claim text.