Abstract: Embodiments for a backlight unit are provided. In one example, a backlight unit comprises a light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide, and a plurality of light sources configured to inject light into the light guide at the first light interface. The example backlight unit also comprises a graded index film configured to receive light from the second light interface of the light guide, homogenize received light that is incident on the graded index film from within a range of acceptance angles and not homogenize light incident on the graded index film from outside of the range of acceptance angles, and direct the homogenized light toward an eye box.

Abstract: Embodiments for a backlight unit are provided. In one example, a backlight unit comprises a light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide, and a plurality of light sources configured to inject light into the light guide at the first light interface. The example backlight unit also comprises a graded index film configured to receive light from the second light interface of the light guide, homogenize received light that is incident on the graded index film from within a range of acceptance angles and not homogenize light incident on the graded index film from outside of the range of acceptance angles, and direct the homogenized light toward an eye box.

Abstract: Embodiments for optical diffusion devices are provided. In one example, an optical diffusion device comprises a first optical element including a first diffusing surface, a second optical element including a second diffusing surface, and an adhesive layer optically coupling the first diffusing surface to the second diffusing surface.

Abstract: Embodiments for a high-efficiency, high-uniformity projection screen are provided. In one example, a projection screen comprises an angle-dependent diffusing layer configured to transmit light non-diffusively within a first range of incident angles and transmit light diffusively within a second range of incident angles and a redirective element configured to receive light transmitted through the angle-dependent diffusing layer in one or more directions within the first range of incident angles and redirect the received light back through the angle-dependent diffusing layer in one or more directions within the second range of incident angles.

Abstract: A display system comprises a head-mounted projector including an exit aperture and a projection engine to project image light through the exit aperture. The image light is projected onto a retro-reflective display that reflects image light in a first dimension at above 90% efficiency within a 25 degree exit angular spread and reflects image light in the first dimension below 10% efficiency outside of a 35 degree exit angular spread.

Abstract: A 3D silhouette sensing system is described which comprises a stereo camera and a light source. In an embodiment, a 3D sensing module triggers the capture of pairs of images by the stereo camera at the same time that the light source illuminates the scene. A series of pairs of images may be captured at a predefined frame rate. Each pair of images is then analyzed to track both a retroreflector in the scene, which can be moved relative to the stereo camera, and an object which is between the retroreflector and the stereo camera and therefore partially occludes the retroreflector. In processing the image pairs, silhouettes are extracted for each of the retroreflector and the object and these are used to generate a 3D contour for each of the retroreflector and object.

Abstract: A polymer-dispersed liquid crystal based display is embedded inside a lightguide illuminator sheet which provides illumination of the display without the need for a backlight or frontlight. Light from one or more light sources is coupled into the lightguide sheet and is guided within a range of high angles of incidence within the sheet by total internal reflection. The guided light illuminating portions of the display which are in diffusing state is scattered such that some of the light is allowed to escape total internal reflection, providing visibility of the display. Guided light illuminating portions of the display which are in non-diffusing state remains guided within the lightguide illuminator sheet. Combining multiple lightguide embedded displays can be used to provide a three-dimensional display.

Abstract: An optical sheet that accepts light transmitted at or within a specific entrance cone angle that then redirects and transmits the light within an exit cone that is substantially normal to the sheet's plane. The intensity of the light within the exit cone is substantially uniform for any light source entering the sheet within the sheet's acceptance angle. The optical sheet is made of transparent material with microlens arrays formed on its opposite front and back surfaces. The thickness of the optical sheet is sufficient so that the microlens on the opposite surfaces are separated a distance equal to the microlens focal length, with each microlens on the front and back surfaces having substantially similar size and shape, with centers transversely aligned. When used with one or more light sources located on one surface, the transmitted light through the optical sheet is uniform in intensity across a second surface.

Abstract: An optical sheet that accepts light transmitted at or within a specific entrance cone angle that then redirects and transmits the light within an exit cone that is substantially normal to the sheet's plane. The intensity of the light within the exit cone is substantially uniform for any light source entering the sheet within the sheet's acceptance angle. The optical sheet is made of transparent material with microlens arrays formed on its opposite front and back surfaces. The thickness of the optical sheet is sufficient so that the microlens on the opposite surfaces are separated a distance equal to the microlens focal length, with each microlens on the front and back surfaces having substantially similar size and shape, with centers transversely aligned. When used with one or more light sources located on one surface, the transmitted light through the optical sheet is uniform in intensity across a second surface.