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Exit pupil expander

An exit pupil and expander technology, applied in the field of diffraction display, can solve the problems of image defects, EPE grating loss and interference, reduce image brightness and uniformity, and achieve the effect of good performance

Active Publication Date: 2020-09-11
DISPELIX OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Like all optical gratings, EPE optical gratings generally cause loss and interference
This reduces the brightness and uniformity of the final image and causes image defects such as color imbalance

Method used

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Examples

Experimental program
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Effect test

Embodiment Construction

[0027] When light propagates through an EPE, a complex network of light paths is formed in which energy typically flows in two directions. An exemplary network such as figure 1 shown. The dots show where the rays resulting from the diffraction of the incident ray 11 hit the grating surface. The network structure allows energy to travel along multiple light paths between points within the network. The dashed lines from point A to point B show two example paths. During numerical optimization, the operation of the EPE structure can be enhanced by also allowing the formation of empty regions (voids) inside the EPE and on the peripheral boundaries of the EPE, since not all possible paths are required for energy transfer.

[0028] Figure 2A An incoupling grating 22 to which light is directed from the projector is shown, generally substantially perpendicular to the image plane in the figure. The light is diffracted and propagates in the waveguide to EPE 24 comprising diffractiv...

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PUM

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Abstract

There is provided an exit pupil expander (EPE) for use in a diffractive display, the EPE comprising a plurality of diffractive zones on a waveguide and a plurality of non-diffractive zones between atleast some of the diffractive zones.

Description

technical field [0001] The invention relates to diffraction display technology. In particular, the invention relates to light guide based diffractive display elements comprising an exit pupil expander (EPE). Such display elements may be used in personal displays, such as head-mounted displays (HMDs), for example near-eye displays (NEDs) and heads-up displays (HUDs). Background technique [0002] HMDs and HUDs can be implemented using waveguide technology. Light can be coupled into the waveguide, redirected into the waveguide and coupled out of the waveguide using a diffraction grating. In one conventional display design, light is directed from a projector to an incoupling grating, which diffracts the incident light into a waveguide where it propagates by total internal reflection via the EPE grating toward the outcoupling grating, thereby Expands the viewable area of ​​the display horizontally. EPEs generally comprise a grating whose grating lines are oblique relative to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B27/01G02B27/00G02B27/42G02B5/18G02B6/00
CPCG02B6/00G02B27/0081G02B27/4272G02B27/0172G02B2027/0174G02B27/0101G02B5/1814G02B6/0016G02B6/0038G02B27/0103G02B27/42G02B6/124
Inventor 尤索·奥尔科宁彼得里·米奥哈宁
Owner DISPELIX OY