Integrated eye tracking and laser projection methods with holographic elements of varying optical powers

• US 10,114,222 B2
• Filed: 11/09/2017
• Issued: 10/30/2018
• Est. Priority Date: 05/28/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Thalmic Labs Inc.
• Inventors: Alexander, Stefan, Chapeskie, Jake, Holland, Lloyd Frederick, Mahon, Thomas
• Primary Examiner(s): Ritchie, Darlene M
• Application Number:
  US15/807,746
• Publication Number:
  US 20180136469A1
• Time in Patent Office: 355 Days
• CPC Class Codes: G02B 2027/0107 with optical power
• CPC Class Codes: G02B 2027/0109 comprising details concerning the making of holograms
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

Systems, devices, and methods that integrate eye tracking capability into scanning laser projector (“SLP”)-based wearable heads-up displays are described. An infrared laser diode is added to an RGB SLP and an infrared photodetector is aligned to detect reflections of the infrared light from features of the eye. A holographic optical element (“HOE”) may be used to combine visible light, infrared light, and environmental light into the user'"'"'s “field of view.” The HOE may be heterogeneous and multiplexed to apply positive optical power to the visible light and zero or negative optical power to the infrared light.

Claims

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 light by at least a first laser diode of the laser projector, the visible light representative of at least a portion of the image;

outputting infrared light by an infrared laser diode of the laser projector;

controllably and reflectively scanning both the visible light and the infrared light by a scan mirror of the laser projector;

redirecting both the visible light and the infrared light towards the eye of the user by a wavelength-multiplexed HOE, including applying a first positive optical power to the visible light by a first hologram of the wavelength-multiplexed HOE, and applying a second optical power to the infrared light by a second hologram of the wavelength-multiplexed HOE, the second optical power less than the first optical power, to converge the visible light to a first exit pupil with a first diameter and to converge the infrared light to a second exit pupil with a second diameter larger than the first diameter;

detecting a reflection of at least a portion of the infrared light from the eye of the user by an infrared photodetector; and

determining a position of at least one feature of the eye based on the reflection of at least a portion of the infrared light from the eye of the user detected by the infrared photodetector.

2. The method of claim 1 wherein applying a second optical power that is less than the first optical power to the infrared light by the second hologram of the wavelength-multiplexed HOE includes applying a second optical power that is less than or equal to zero to the infrared light by the second hologram of the wavelength-multiplexed HOE.

3. The method of claim 1 wherein determining a position of at least one feature of the eye based on the reflection of the infrared light from the eye of the user detected by the infrared photodetector includes determining the position of at least one feature of the eye based on the reflection of the infrared light from the eye of the user by a processor.

4. The method of claim 1 wherein outputting visible light by at least a first laser diode of the laser projector includes at least one of:

outputting red light by a red laser diode of the laser projector;

outputting green light by a green laser diode of the laser projector; and

/or

outputting blue light by a blue laser diode of the laser projector.