Laser projector and diffractive display device

Patent metadata

Field	Value
Publication number	US-2021088798-A1
Application number	US-201816954864-A
Country	US
Kind code	A1
Filing date	Dec 14, 2018
Priority date	Dec 22, 2017
Publication date	Mar 25, 2021
Grant date	—

Abstract

The invention relates to a laser projector for presenting an image on a waveguide plane. The projector comprises a laser source (10, 10A, 10B, 10C) capable of emitting a polychromatic light beam (11) or a plurality of narrow-wavelength light beams (11A, 11B, 11C), and a guidance element (12A, 12B) for directing light emitted by the light source to different pupils (16A, 16B, 16C) of the waveguide plane, the different pupils being displaced with respect to each other in the waveguide plane. The invention also concerns a personal display device comprising such projector.

First claim

1 . A laser projector for presenting an image on a waveguide plane, comprising:
a laser source capable of emitting a plurality of narrow-wavelength light beams, and a guidance element for directing light emitted by the laser source to different pupils of the waveguide plane, the different pupils being displaced with respect to each other in said waveguide plane, wherein:
the laser source and guidance element are adapted to produce at least three narrow-wavelength beams spatially separated on the waveguide plane into said different pupils, and
the laser source and guidance element are adapted direct said narrow-wavelength beams in different angles to said different pupils, whereby the laser source comprises at least three different laser sub-sources adapted to produce at least three initial beams corresponding to said at least three narrow-wavelength beams, the initial beams propagating at different angles onto the guidance element, and the guidance element is further adapted to reflect the initial beams at different angles towards said different pupils, respectively.

2 . The projector according to claim 1 , wherein the sub-sources are laser sources at different locations and angles directed towards the guidance element.

3 . The projector according to claim 1 , wherein the laser source comprises three laser sources and a prismatic coupler adapted to produce said narrow-wavelength beams at different angles towards the guidance element.

4 . The projector according to claim 1 , wherein the guidance element comprises one or more microelectromechanical mirrors.

5 . The projector according to claim 1 , wherein the guidance element is movable so as to produce a scanning beam onto different locations within said input pupils in order to form the image.

6 . The projector according to claim 1 , wherein said different pupils are located linearly or triangularly with respect to each other on the waveguide plane and do not overlap each other.

7 . A diffractive personal display device, comprising:
a diffractive waveguide having a waveguide plane and comprising at least three input pupils displaced from each other in the waveguide plane, and a projector according to claim 1 , for projecting at least three narrow-wavelength light beams to the input pupils.

8 . The device according to claim 7 , wherein the waveguide comprises at least three waveguide layers and the input pupils are located at different layers.

9 . The device according to claim 8 , wherein each input pupil comprises a diffractive in-coupling grating and the waveguide further comprises a plurality of out-coupling gratings aligned with each other for presenting a polychromatic image for a user.

10 . The device according to claim 7 , wherein each input pupil comprises a diffractive in-coupling grating and the waveguide further comprises a plurality of out-coupling gratings aligned with each other for presenting a polychromatic image for a user.

11 . A diffractive personal display device, comprising:
a diffractive waveguide having a waveguide plane and comprising at least three input pupils displaced from each other in the waveguide plane, and a projector according to claim 2 , for projecting at least three narrow-wavelength light beams to the input pupils.

12 . The device according to claim 11 , wherein the waveguide comprises at least three waveguide layers and the input pupils are located at different layers.

13 . The projector according to claim 2 , wherein the laser source comprises three laser sources and a prismatic coupler adapted to produce said narrow-wavelength beams at different angles towards the guidance element.

14 . The projector according to claim 12 , wherein the guidance element comprises one or more microelectromechanical mirrors.

15 . The projector according to claim 13 , wherein the guidance element is movable so as to produce a scanning beam onto different locations within said input pupils in order to form the image.

16 . The projector according to claim 2 , wherein the guidance element comprises one or more microelectromechanical mirrors.

17 . The projector according to claim 3 , wherein the guidance element comprises one or more microelectromechanical mirrors.

18 . The projector according to claim 2 , wherein the guidance element is movable so as to produce a scanning beam onto different locations within said input pupils in order to form the image.

19 . The projector according to claim 3 , wherein the guidance element is movable so as to produce a scanning beam onto different locations within said input pupils in order to form the image.

20 . The projector according to claim 4 , wherein the guidance element is movable so as to produce a scanning beam onto different locations within said input pupils in order to form the image.

Assignees

• Dispelix Oy

Inventors

• Blomstedt Kasimir
• Olkkonen Juuso
• Aikio Mika

Classifications

• G02B27/0101

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B5/18 Primary

  Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} · CPC title

• G03B21/28

  Reflectors in projection beam {(in illumination beam G03B21/2066)} · CPC title

• G02B26/10

  Scanning systems · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title