Addressable VCSEL Eye-Box Illumination for Lower Power Eye Tracking
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Solution Overview
Problem
Conventional optical devices, such as head-mounted displays, waste power and generate excessive heat due to illuminating the entire eye box region with infrared light, even where the iris, pupil, and cornea are not located, leading to reduced battery life and inefficiency.
Innovation Solution
The use of independently addressable VCSEL subarrays within an optical device, which are dynamically controlled to illuminate only specific subregions of the eye box region based on the user's eye relief, reducing power consumption and increasing energy efficiency by targeting the corneal surface with adjustable illumination cones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the entire eye box region is illuminated with infrared light to ensure adequate illumination for all users, then the illumination uniformity and coverage are improved, but the power consumption increases and battery life decreases
Solution Approach 1:
The VCSEL array is divided into multiple independently addressable subarrays that can be selectively activated. Instead of illuminating the entire eye box region uniformly, the system segments the illumination into specific subregions corresponding to where the user's eye structures are likely to be positioned, thereby reducing power consumption while maintaining adequate illumination where needed.
Solution Approach 2:
The illumination is made non-uniform by directing light only to specific subregions of the eye box rather than the entire region. This local quality approach concentrates optical power where it is most needed (at probable eye positions) while leaving other areas unilluminated, thus reducing overall power consumption without sacrificing illumination effectiveness.
2Adaptability or versatility
If the entire eye box region is illuminated to accommodate variations in facial structure among users, then the adaptability to different users is improved, but the heat generation increases
Solution Approach 1:
The illumination pattern is made dynamic and adjustable rather than static and uniform. The system can adaptively activate different combinations of VCSEL subarrays based on detected eye positions or predicted eye box regions, allowing it to accommodate different users and facial structures while minimizing heat generation by activating only the necessary subarrays for each situation.
3Area of stationary object
If VCSEL arrays are configured to provide sufficient optical power across the entire eye box region, then the illumination coverage is improved, but the device complexity increases
Solution Approach 1:
The VCSEL array is segmented into multiple independently controllable subarrays, each capable of being addressed separately. This segmentation allows the system to cover the entire eye box region by selectively activating appropriate subarrays based on eye position, achieving comprehensive coverage while simplifying control through modular addressing schemes rather than requiring complex continuous adjustment mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances energy efficiency and reduces power consumption while maintaining adequate illumination for eye tracking systems, extending battery life and minimizing heat generation by dynamically adjusting illumination to match individual eye structures.
Implementation Method 1
Light emitting diodes (LED) or laser light sources are often used to illuminate with infrared light a volume of three-dimensional space in which a user's eyes may be positioned
Implementation Method 2
one or more vertical cavity surface emitting laser (VCSEL) arrays arranged in the body of the optical device
Data Source
AI summary
An optical device is provided, including a body formed to have a concavity within which an eye box region is defined; and a plurality of addressable vertical cavity surface emitting laser (VCSEL) arrays arranged in the body of the optical device. The one or more VCSEL arrays comprise a plurality of VCSEL subarrays including independently addressable first and second VCSEL subarrays, which are controlled so as to power the first VCSEL subarray and not the second VCSEL subarray to illuminate only a first subregion of the eye box region, or to power the second VCSEL subarray and not the first VCSEL subarray to only illuminate a second subregion of the eye box region.