Optical system and method for improvement of light field uniformity

A display device for displaying images to a viewer, the display device comprising:

• an optical system including a light-guiding optical element (LOE) having a pair of major surfaces that receives light from an image projecting arrangement such that the light is guided through the LOE by internal reflection at the major surfaces, the light received from the image projecting arrangement being indicative of a collimated image to be displayed to the viewer and being produced by the image projecting arrangement from input image data, the LOE further including at least one partially reflective surface oblique to the major surfaces, the at least one partially reflective surface directing the guided light out of the LOE to produce, at an exit pupil defined by the at least one partially reflective surface, output light having a field of view (FOV) corresponding to the collimated image, the LOE defining a characterizing intensity transfer function map Ii(x,φ) of the optical system across a lateral dimension x of the exit pupil and an angular span φ of the FOV;
• and
• a control unit including:
• an intensity map generator module that convolves data indicative of the characterizing intensity transfer function map I1(x,φ) over a predetermined dimension x′ of the eye pupil of the viewer and a predetermined lateral offset (x′−x) between the exit pupil and the eye pupil to obtain data indicative of a convolved intensity transfer function map I′1((x′−x),φ) that is indicative of angular intensity transfer from the exit pupil to the predetermined dimension x′ of the eye pupil, and generates a correction intensity map from the convolved intensity transfer function map I′1((x′−x),φ), and
• an intensity map modulator that generates, based on the correction intensity map, corresponding intensity modulation to be applied to the input image data, the intensity modulation affecting the image data to at least partially compensate intensity non-uniformity in the characterizing intensity transfer function map I1(x,φ) of the optical system such that the output light at the exit pupil has a modulated intensity map observed by the viewer with improved intensity uniformity.