Abstract: A diffractive grating element is divided into at least two different grating regions each having different diffractive properties and arranged on opposite sides with respect to a transition point to form a splitted grating structure. The diffractions generated by the at least two different grating regions are arranged to mutually compensate for the variation in the input angle of the incident light wave to the total diffraction efficiency of the at least one diffracted light wave that is arranged to propagate within the substrate.

Abstract: A method and optical system for coupling light from an incoming light wave (WI) into a waveguiding substrate (S) arranges the light wave (WI) to interact with a diffractive in-coupling grating element or elements (IG) arranged on or embedded within the substrate (S) and arranged to couple the energy from the light wave (WI) into a waveguided light wave (WG). The polarization state of the light wave (WI) is converted after its first interaction (D1) with the in-coupling grating element/elements (IG) and before a second interaction (D2) with the grating element/elements (IG) takes place. The method minimizes any “reverse” diffractions, which would direct light back towards the front-end optics and therefore to increase the width W of the in-coupling grating/gratings (IG). Preferred embodiments include diffractive beam expanders for virtual displays.

Abstract: A planar substrate having a first diffractive element for coupling light waves of different colors into the substrate and guiding the light waves by successive internal reflections. A second diffractive element, disposed on the substrate, causes the guided light waves to be partially transmitted out of the substrate where the light waves encounter the second diffractive element. Because light waves of each color are reflected at different reflection angles, the light waves with smaller reflection angles encounter the second diffractive element at more locations than those with larger reflection angles, resulting in color non-uniformity in the light transmitted out from the substrate surface. One or more interfaces are provided between the surfaces of the substrate to selectively reflect the light waves having larger reflection angles toward the second diffraction element, so that light waves of different colors encounter the second diffraction element substantially at the same number of locations.

Abstract: A direct view display device based on light reflection and diffraction from a deformable material layer under influence of an electric field. The display device comprises a plurality of pixel cells, each cell has at least a first prism surface to support the deformable material, such that when the electric field is off, a light beam travels through the first prism surface and the deformable material is reflected via total internal reflection through the first prism surface to a second prism surface, whereby the light beam is directed toward a beam blocker. When the electric field is on, the deformable material forms a rippled surface to diffract the encountering light beam, allowing part of the light beam to avoid the beam blocker. A microlens is used for each pixel cell to focus the light beam at the beam blocker.

Abstract: A portable device having an optical engine adapted to form an image from an image source in four different modes to allow a viewer to view the image. The image source is a microdisplay device, which can be reflective, transmissive or emissive. The display modes include a near-eye display (NED) mode, a near projection display (NPD) mode, a Window mode that provides a virtual image to a viewer at a distance, and a projection display mode that projects an image on a surface at a distance. The portable device has an internal light source to provide illumination to the image source for the first three modes. The portable device is further adapted to receive the light output from an external light source for use with the fourth mode.

Abstract: A device and a method for tracking an eye-gaze of an observer. A deep blue or violet light source is used to emit light to eye, particularly to the retina. The deep blue light is partially reflected and partially absorbed by the retina. The absorption is most prominent around the fovea, the area of sharp vision, because of the pigment which protects the fovea from short wavelength radiation. Thus the device and method of tracking eye-gaze according to the invention comprises emitting light having a certain wavelength and transferring the light to the retina of an eye. The wavelength of the light being such as to make the fovea of the eye resolvable. The method further comprises detecting light that is reflected from the eye to form detection information including the resolvable fovea, and mapping the detection information to a predetermined surface, the surface being located at a distance from the eye, the location of the fovea on the surface forming an eye-gaze point.

Abstract: The invention relates to an optical device (50) for manipulating a light wave (&lgr;) using a diffractive grating structure (G). According to the basic idea behind the invention a prior art type diffractive grating structure having a permanently shaped surface relief is substituted with an electrically deformable diffractive grating structure (G), where a preformed, basic surface relief of the grating is composed of dielectric and deformable viscoelastic material, which can be electrically and sequentially fine tuned in shape to adjust the diffraction properties of said grating individually for different wavelengths. The invention permits manufacture of virtual display devices with a significantly larger exit pupil diameter than prior art solutions without degrading the color uniformity of the display device.

Abstract: A planar substrate having a first diffractive element for coupling light waves of different colors into the substrate and guiding the light waves by successive internal reflections. A second diffractive element, disposed on the substrate, causes the guided light waves to be partially transmitted out of the substrate where the light waves encounter the second diffractive element. Because light waves of each color are reflected at different reflection angles, the light waves with smaller reflection angles encounter the second diffractive element at more locations than those with larger reflection angles, resulting in color non-uniformity in the light transmitted out from the substrate surface. One or more interfaces are provided between the surfaces of the substrate to selectively reflect the light waves having larger reflection angles toward the second diffraction element, so that light waves of different colors encounter the second diffraction element substantially at the same number of locations.

Abstract: A device and a method for tracking an eye-gaze of an observer. A deep blue or violet light source is used to emit light to eye, particularly to the retina. The deep blue light is partially reflected and partially absorbed by the retina. The absorption is most prominent around the fovea, the area of sharp vision, because of the pigment which protects the fovea from short wavelength radiation. Thus the device and method of tracking eye-gaze according to the invention comprises emitting light having a certain wavelength and transferring the light to the retina of an eye. The wavelength of the light being such as to make the fovea of the eye resolvable. The method further comprises detecting light that is reflected from the eye to form detection information including the resolvable fovea, and mapping the detection information to a predetermined surface, the surface being located at a distance from the eye, the location of the fovea on the surface forming an eye-gaze point.

Abstract: A portable device having an optical engine adapted to form an image from an image source in four different modes to allow a viewer to view the image. The image source is a microdisplay device, which can be reflective, transmissive or emissive. The display modes include a near-eye display (NED) mode, a near projection display (NPD) mode, a Window mode that provides a virtual image to a viewer at a distance, and a projection display mode that projects an image on a surface at a distance. The portable device has an internal light source to provide illumination to the image source for the first three modes. The portable device is further adapted to receive the light output from an external light source for use with the fourth mode.

Abstract: A light valve capable of operating in an “off” state for reflecting light and in an “on” state for diffracting and reflecting light. The valve includes a semiconductor substrate having a plurality of electrodes formed therein for receiving voltages and for generating an electric field in response to the received voltages. A layer of transparent deformable dielectric material is disposed on the reflective electrodes which deforms in response to the generated electric field. When the valve is in its “on” state, the electric field causes deformities in the dielectric material which diffract incident light reflected off of the valve. In another embodiment, the dielectric material is placed on the reflective electrodes or on a transparent substrate having a transparent electrode formed thereon. The transparent substrate is then disposed in spaced relation from the semiconductor substrate containing the reflective electrodes.

Abstract: A light valve capable of operating in an “off” state for reflecting light and in an “on” state for diffracting and reflecting light. The valve includes a semiconductor substrate having a plurality of electrodes formed therein for receiving voltages and for generating an electric field in response to the received voltages. A layer of transparent deformable dielectric material is disposed on the reflective electrodes which deforms in response to the generated electric field. When the valve is in its “on” state, the electric field causes deformities in the dielectric material which diffract incident light reflected off of the valve. In another embodiment, the dielectric material is placed on a transparent substrate having a transparent electrode formed therein, and is disposed in spaced relation from the semiconductor substrate containing the reflective electrodes.

Abstract: A method and apparatus in Molecular Beam Epitaxy (MBE) in order to grow thin films. The substrate is attached to the rotatable manipulator and its normal will be aligned parallel to the rotation axis in vacuum for providing a real time information on the growth parameters by ellipsometry. The apparatus includes a rotatable manipulator head where the substrate is attached to, and aligning elements to align the substrate normal sufficiently parallel to the rotation axis of the manipulator in vacuum.