Method of forming an image and image projection device

A method of forming an image in a replay field of a device carrying a distribution of phase information, the method comprising causing the phase information to impart a spherical characteristic onto image-representative phase information, illuminating the device with collimated light, and focusing zero order light from the device at a focal region, whereby the spherical characteristic causes the replay field to be beyond the focal region.

A method of projecting an image, the method comprising writing data to a spatial light modulator, illuminating the spatial light modulator with collimated lights so that the spatial light modulator provides generally-collimated output beam, applying the output beam to a converging lens so that zero-order light undiffracted by the SLM is focused at a first location, wherein the data written to the SLM comprises image data, characterized in that the data written to the spatial light modulator further comprises data for causing the image to be formed beyond the first location.

A method of projecting an image, the method comprising writing data to a spatial light modulator, illuminating the spatial light modulator with light so that the spatial light modulator provides an output beam, applying the output beam to a Fourier lens, whereby light undiffracted by the SLM is focused substantially at the focus of the Fourier lens, wherein the data written to the spatial light modulator comprises phase data retrieved from a target image, the image data being modified so that in concert with the Fourier lens the image content of the output beam forms a replay field beyond the focus of the Fourier lens.

A method for blocking zero-order light from a replay field, comprising providing a pixilated device with a phase distribution that when illuminated would provide a holographic image at a replay plane via a Fourier lens and which phase distribution causes the replay plane to be located beyond the focus of the Fourier lens, and providing a device preventing light from the focus of the Fourier lens from reaching the replay plane.

An image projection device comprising a device for imparting respective phase-shifts to different regions of an incident wavefront, wherein the phase shifts give rise to an image in a replay field, and means for causing zero-order light to be focused into a region between the replay field and the device.