Envisics Ltd

A holographic projector includes a display device arranged to form a holographic wavefront by spatially modulating light in accordance with a hologram of a picture. The holographic projector includes a magnification system including a first and second lens. The first lens is arranged form a holographic reconstruction of the picture by focusing the holographic wavefront towards a front focal plane of the first lens. The holographic reconstruction of the picture includes a plurality of pixels. The holographic projector includes a kinoform disposed between the first and second lens and arranged to apply a phase-delay to each pixel of the holographic reconstruction. The holographic projector includes a movement assembly arranged to move the kinoform such that a plurality of different phase-delays are applied to each pixel. The kinoform includes an array of zones and is arranged such that the width of each zone is substantially equal to the distance between adjacent pixels.

A method is provided of manufacturing a waveguide comprising an input port, an output port, a transparent medium having a first refractive index (n 1 ), a first pair of opposing surfaces and a second pair of opposing surfaces. The method comprises polishing at least one surface of the second pair of opposing surfaces to achieve a separation therebetween, bonding a protective layer to at least one polished surface of the second pair of opposing surfaces; and polishing at least one surface of the first pair of opposing surfaces to achieve a separation therebetween.

An etendue expander for a display. The etendue expander comprises a first lens arranged to form a holographic reconstruction of a hologram displayed at a first focal plane thereof. The holographic reconstruction comprises a plurality of pixels. The etendue expander comprises a plurality of microlenses. Each microlens is aligned with a respective pixel of the holographic reconstruction to form an image of the plurality of pixels. The etendue expander comprises a second lens arranged such that the image of the plurality of pixels is disposed at a first focal plane thereof and a relayed hologram is formed at a second focal plane thereof. The etendue of the relayed hologram is greater than that of the hologram.

A head-up display is provided. The head-up display comprises an optical component comprising a surface arranged, during head-up display operation, in a configuration that is conducive to sunlight glare. The head-up display further comprises a reflection suppression device arranged to receive sunlight on an optical path to the surface. The reflection suppression device comprises a lattice structure. The lattice structure extends in a first direction and a second direction. The lattice structure forms a plurality of channels extending in a third direction. Each channel is defined by a respective axis having a first angle in the first direction and second angle in the second direction. The first angle is a function of the first direction.

A method comprising: applying a respective value of a first plurality of values of a first control parameter to each light source of a projector system, wherein each of the first plurality of values of the first control parameter determines an output luminance of a corresponding light source; measuring a first luminance and first colour space coordinates of a light pattern displayed based on the first plurality of values; converting the first luminance and first colour space coordinates to corresponding tristimulus values; calculating therefrom a respective colour luminance value corresponding to each light source; calculating a linear relationship between the first control parameter and each colour luminance value; determining a second plurality of values of the first control parameter based on the linear relationships and a target colour luminance value for each light source; and controlling the plurality of light sources using the second plurality of values.

A display system comprises a waveguide forming a pupil expander. The waveguide comprises a pair of opposing surfaces arranged to guide a diffracted light field therebetween by internal reflection. An input port of the waveguide is arranged to receive light from a display system. An output port of the waveguide is formed by a first transmissive-reflective element of a first surface of the pair of opposing surfaces. The first transmissive-reflective element is such that the diffracted light field is divided at each internal reflection and a plurality of replicas of the diffracted light field are transmitted out of the waveguide through the output port. The input port comprises a second transmissive-reflection element arranged to receive at least a portion of the light from the display system.

A projection system comprising a display device, a hologram engine and a waveguide. The display device is arranged to display a hologram of an image and spatially modulate light in accordance with the hologram to form a holographic wavefront. The hologram engine is arranged to calculate the hologram. The hologram is arranged to angularly distribute light within the holographic wavefront in accordance with spatial position within the image such that continuous angular ranges of the holographic wavefront respectively correspond with continuous regions of the image. The waveguide comprising a pair of parallel reflective surfaces arranged to waveguide the holographic wavefront therebetween. A first surface of the pair of parallel reflective surfaces is partially reflective-transmissive so as to form an output comprising a plurality of emission zones for the holographic wavefront. The hologram engine is arranged to modify the hologram to at least partially compensate for a decrease in intensity of the emission from each successive emission zone of the waveguide caused by the partial reflection-transmissions at the first surface during waveguiding.

Systems and methods disclosed herein include, among other aspects, a head-up display comprising an eye-box having a first dimension and a second dimension, where the head-up display is arranged to form first image content in a first image area at a first image area distance from the eye-box and second image content in a second image area at a second image area distance from the eye-box, where the first image area distance is less than the second image area distance and the first image area is at least partially overlapping in the first dimension with the second image area, and where the second image area extends less far in angular space than the first image area in at least one direction of the first dimension.

Disclosed embodiments include a replicator arranged to receive spatially modulated light and replicate the spatially modulated light to form a plurality of replicas of the spatially modulated light by waveguiding between a reflective surface and a transmissive-reflective surface. The transmissive-reflective surface forms an output surface for the plurality of replicas of the spatially modulated light. Some embodiments additionally include a light control device (i) located in an optical path of the plurality of replicas of the spatially modulated light downstream from the output surface of the replicator, and (ii) arranged to provide a first angular turn to the replicas of the spatially modulated light. The first angular turn is caused by refractive power and has a primary component on a plane. Some embodiments also include a diffractive optical element arranged to provide a second angular turn to the spatially modulated light or the replicas thereof.

There is provided a method of calibrating a holographic projector. The method comprises displaying a primary diffractive pattern on a display device, wherein the primary diffractive pattern comprises a first hologram of a first target image and a phase-ramp function. The method further comprises illuminating the primary diffractive pattern to form a first holographic reconstruction of the first target image on a replay plane. The first target image comprises a picture area and a non-picture area. The phase-ramp function is arranged to translate the first holographic reconstruction. The method further comprises blocking at least a portion of the first holographic reconstruction using a mask, wherein the mask is arranged to block the non-picture area in the absence of the phase-ramp function. The method further comprises measuring a property of a boundary between the picture area and the non-picture area. There is further provided a holographic projection system.