Methods that integrate visible light eye tracking in scanning laser projection displays

Patent metadata

Field	Value
Publication number	US-10180578-B2
Application number	US-201715807856-A
Country	US
Kind code	B2
Filing date	Nov 9, 2017
Priority date	May 28, 2015
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

Systems, devices, and methods that integrate eye tracking capability into scanning laser projector (“SLP”)-based wearable heads-up displays are described. At least one narrow waveband laser diode is used in an SLP to define one or more portion(s) of a visible image. At least one corresponding narrow waveband photodetector is aligned to detect reflections of the portion(s) of the image from features of the eye. A holographic optical element (“HOE”) may be used to combine the image and environmental light into the user's “field of view.” Three narrow waveband photodetectors each responsive to a respective one of three narrow wavebands output by the RGB laser diodes of an RGB SLP are aligned to detect reflections of a projected RGB image from features of the eye.

First claim

The invention claimed is:

1. A method of operating a laser projector to project an image to an eye of a user and to track the eye of the user, the method comprising:
outputting visible laser light by a laser module, wherein the laser module includes at least a first laser diode and a second laser diode, and outputting visible laser light by the laser module includes outputting a first visible laser light in a first narrow waveband from the first laser diode of the laser module and outputting a second visible laser light in a second narrow waveband from the second laser diode, the second narrow waveband different from the first narrow waveband, wherein the first visible laser light is representative of at least a first portion of a displayed image and the second visible laser light is representative of at least a second portion of the displayed image;
controllably and reflectively scanning the first visible laser light and the second visible laser light by a scan mirror;
redirecting the visible laser light towards the eye of the user by a wavelength-multiplexed HOE comprising a first hologram that is responsive to light in the first narrow waveband and unresponsive to light that is outside the first narrow waveband and a second hologram that is responsive to light in the second narrow waveband and unresponsive to light that is outside the second narrow waveband, wherein redirecting the visible laser light towards the eye of the user by the wavelength-multiplexed HOE includes redirecting the first portion of the displayed image towards the eye of the user by the first hologram of the wavelength-multiplexed HOE and redirecting the second portion of the displayed image towards the eye of the user by the second hologram of the wavelength-multiplexed HOE, and wherein the wavelength-multiplexed HOE is substantially transparent to environmental light;
detecting a reflection of at least a portion of the visible laser light from the eye of the user by at least a first narrow waveband photodetector and a second narrow waveband photodetector, wherein the first narrow waveband photodetector is responsive to light in the first narrow waveband and substantially unresponsive to light that is outside of the first narrow waveband, the second narrow waveband photodetector is responsive to light in the second narrow waveband and substantially unresponsive to light that is outside of the second narrow waveband, and wherein detecting a reflection of the at least a portion of the visible laser light from the eye of the user by at least a first narrow waveband photodetector and a second narrow waveband photodetector includes detecting a reflection of the first portion of the displayed image by the first narrow waveband photodetector and detecting a reflection of the second portion of the displayed image from the eye of the user by the second narrow waveband photodetector; and
determining a position of at least one feature of the eye based on at least the reflection of the first portion of the displayed image from the eye of the user detected by the first narrow waveband photodetector and the reflection of the second portion of the displayed image from the eye of the user detected by the second narrow waveband photodetector.

2. The method of claim 1 , wherein redirecting the visible laser light towards the eye of the user by a wavelength-multiplexed HOE includes converging, by the wavelength-multiplexed HOE, the first visible laser light and the second visible laser light towards a first exit pupil at the eye of the user.

3. The method of claim 1 wherein:
the laser module includes a third laser diode and outputting visible light by a laser module further includes outputting a third visible laser light in a third narrow waveband by the third laser diode of the laser module, the third narrow waveband different from both the first narrow waveband and the second narrow waveband, and wherein the third visible laser light is representative of at least a third portion of the displayed image;
controllably and reflectively scanning the visible laser light by a scan mirror further includes controllably and reflectively scanning the third portion of the displayed image by the scan mirror;
the wavelength-multiplexed HOE further comprises a third hologram that is responsive to light in the third narrow waveband and unresponsive to light that is outside the third narrow waveband and redirecting the visible laser light towards the eye of the user by the wavelength-multiplexed HOE further includes redirecting the third portion of the displayed image towards the eye of the user by the third hologram of the wavelength-multiplexed HOE;
detecting a reflection of at least a portion of the visible laser light from the eye of the user by at least a first narrow waveband photodetector further includes detecting a reflection of the third portion of the displayed image from the eye of the user by a third narrow waveband photodetector, wherein the third narrow waveband photodetector is responsive to light in the third narrow waveband and substantially unresponsive to light that is outside of the third narrow waveband; and
wherein determining a position of at least one feature of the eye further includes determining a position of at least one feature of the eye based on the reflection of the third portion of the displayed image from the eye of the user detected by the third narrow waveband photodetector.

4. The method of claim 3 wherein:
the first laser diode is a red laser diode, outputting a first visible laser light in a first narrow waveband by the first laser diode of the laser module includes outputting a red laser light by the red laser diode, and the first portion of the displayed image is a red portion of the displayed image;
the second laser diode is a green laser diode, outputting a second visible laser light in a second narrow waveband by the second laser diode of the laser module includes outputting a green laser light by the green laser diode, and the second portion of the displayed image is a green portion of the displayed image; and
the third laser diode is a blue laser diode, outputting a third visible laser light in a third narrow waveband by the third laser diode of the laser module includes outputting a blue laser light by the blue laser diode, and the third portion of the displayed image is a blue portion of the displayed image.

Assignees

• Thalmic Labs Inc
• North Inc

Inventors

• Alexander Stefan
• Chapeskie Jake
• Holland Lloyd Frederick
• Mahon Thomas

Classifications

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · 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

• G02B27/0176

  characterised by mechanical features · CPC title

• G02B27/0093

  with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking · CPC title

• G02B2027/0107

  with optical power · CPC title