US 12,443,038 B2
Pupil expander
Neil Collings, Milton Keynes (GB); and Alexander Cole, Milton Keynes (GB)
Assigned to Envisics Ltd, Milton Keynes (GB)
Appl. No. 17/780,057
Filed by Envisics Ltd, Milton Keynes (GB)
PCT Filed Dec. 2, 2020, PCT No. PCT/EP2020/084267
§ 371(c)(1), (2) Date May 26, 2022,
PCT Pub. No. WO2021/110746, PCT Pub. Date Jun. 10, 2021.
Claims priority of application No. 1917584 (GB), filed on Dec. 2, 2019.
Prior Publication US 2023/0333374 A1, Oct. 19, 2023
Int. Cl. G02B 27/01 (2006.01)
CPC G02B 27/0103 (2013.01) [G02B 27/01 (2013.01); G02B 2027/0123 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A display system having a viewing window on a viewing plane, wherein the display system comprises:
a picture generating unit arranged to display a picture on a display plane, wherein the picture is a holographic reconstruction formed from a hologram of the picture; and
an imaging system arranged to form an image of the picture that is viewable from the viewing window, wherein the imaging system comprises:
a projection lens disposed between the display plane and the viewing plane, wherein the projection lens is a simple lens arranged to magnify the picture and to form an image of the picture on an image plane;
an aperture stop arranged to restrict an aperture of the projection lens in a first direction and function as a limiting aperture stop of the imaging system, wherein the aperture stop includes a mask comprising a rectangular window, wherein the mask is configured to block light rays emitted from a peripheral section of the projection lens in the first direction, and wherein the rectangular window has a size in the first direction that is less than a diameter of the projection lens in the first direction; and
a first waveguide pupil expander arranged to receive light of the picture from the projection lens through the aperture stop and replicate the aperture stop in order to expand the viewing window of the display system in the first direction.