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1. (WO2018202951) DISPLAY ELEMENT, PERSONAL DISPLAY DEVICE, METHOD OF PRODUCING AN IMAGE ON A PERSONAL DISPLAY AND USE

Pub. No.:    WO/2018/202951    International Application No.:    PCT/FI2018/050322
Publication Date: Fri Nov 09 00:59:59 CET 2018 International Filing Date: Fri May 04 01:59:59 CEST 2018
IPC: G02B 27/00
G02B 27/01
G02B 27/10
G02B 27/42
G02B 5/18
Applicants: DISPELIX OY
Inventors: OLKKONEN, Juuso
SUNNARI, Antti
Title: DISPLAY ELEMENT, PERSONAL DISPLAY DEVICE, METHOD OF PRODUCING AN IMAGE ON A PERSONAL DISPLAY AND USE
Abstract:
The invention concerns a display element for a personal display system, a personal display, a method and a use. The display element comprises a lightguide (21) capable of guiding light by total internal reflections, a diffractive in-coupling grating (22), and a diffractive out-coupling grating (25). The in- coupling grating is adapted to couple light directed thereto to the lightguide so as to allow propagation of the light to the out-coupling grating. According to the invention, the in-coupling grating is adapted to couple light to the lightguide as at least two diffraction wavefronts and the display element further comprises at least two different exit pupil expander gratings (23, 24) adapted to guide said wavefronts respectively to the out-coupling grating along different paths. The invention allows for reducing the size of diffractive display elements.