How Eye Trackers Detect Eyelid Movements and Blinks
This patent describes a method for eye tracking systems to precisely detect eyelid movements and blinks by comparing a current eye image to a reference image, then analyzing the differences in rows of pixels.
Original patent title: “Eye tracking system”
This patent describes a method for eye tracking systems to precisely detect eyelid movements and blinks by comparing a current eye image to a reference image, then analyzing the differences in rows of pixels. Owned by Tobii AB with 23 claims and 1 forward citation, and it is expected to expire in 2042.
Coverage
What does this patent actually cover?
This eye tracking system works by taking two pictures of a user's eye: a 'reference image' and a 'current image' (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). It then finds the differences between these two images, creating a 'differential image' where only what has changed is visible. This differential image is like a grid of pixels, each showing how much it changed (Claim 1). The system then adds up or combines the change values in each horizontal row of pixels to get 'row values' (Claim 1, Claim 6). Finally, it uses these row values to figure out 'eyelid data,' such as the exact position of an eyelid edge (Claim 7) or whether the eye is blinking (Claim 9). For example, if you blink, the system would see a big change in certain rows of the differential image, indicating a blink.
The gap
What does this patent NOT cover?
- Does not cover eye tracking systems that detect eyelid movement without first creating a differential image by comparing a current image to a reference image.
- Does not cover systems that determine eyelid data solely from analyzing individual pixels or columns, rather than combining differential intensity values in corresponding rows (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Does not cover eye tracking methods that rely only on infrared reflections or pupil dilation without image differencing for eyelid detection.
- Does not cover systems that track the entire eye's movement without specifically processing images to extract eyelid location or blink data.
- Does not cover methods for determining eyelid data that do not involve a two-dimensional pixel array with differential intensity values.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The clever part is using a 'differential image' created by subtracting a reference image from a current one, then combining pixel intensity differences specifically along rows. This highlights only the eyelid movement, making it easier and potentially faster to detect changes like blinks or eyelid position without needing complex analysis of the entire eye image.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Virtual reality headsets with eye tracking
Augmented reality glasses
Driver monitoring systems in cars
Assistive technologies for people with disabilities
Gaming peripherals with eye control
Market research tools for attention analysis
Clinical diagnostic tools for eye conditions
Why it matters
The bigger picture
Accurate eyelid tracking is crucial for many applications, from understanding user attention in virtual reality to diagnosing neurological conditions. By precisely identifying eyelid positions and blinks, this technology can improve the reliability of eye-tracking data, making it more useful for both research and commercial products. This precision helps prevent false readings and provides richer information about a user's state.
Filed
June 30, 2022
Market context
Who's building on this
Companies in this space
Tobii AB, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more → of this patent, is a leading company in the eye-tracking industry, developing hardware and software for various applications, including research, gaming, and assistive technology. Other companies like Meta (with their VR headsets) and various automotive suppliers are also heavily invested in advanced eye-tracking solutions that could leverage or build upon such techniques for improved performance.
Market impact
This patent contributes to the ongoing refinement of eye-tracking technology, which is becoming increasingly integrated into consumer electronics and specialized applications. By offering a more robust and potentially efficient way to detect eyelid movements and blinks, it enables more accurate and nuanced user interaction and data collection. This can lead to better user experiences in VR/AR, more reliable driver safety systems, and more precise insights in fields like neuroscience and marketing research.
Claim 1 — Plain English
What this patent covers
This eye tracking system works by taking two pictures of a user's eye: a 'reference image' and a 'current image' (Claim 1). It then finds the differences between these two images, creating a 'differential image' where only what has changed is visible. This differential image is like a grid of pixels, each showing how much it changed (Claim 1). The system then adds up or combines the change values in each horizontal row of pixels to get 'row values' (Claim 1, Claim 6). Finally, it uses these row values to figure out 'eyelid data,' such as the exact position of an eyelid edge (Claim 7) or whether the eye is blinking (Claim 9). For example, if you blink, the system would see a big change in certain rows of the differential image, indicating a blink.
The clever bit
The clever part is using a 'differential image' created by subtracting a reference image from a current one, then combining pixel intensity differences specifically along rows. This highlights only the eyelid movement, making it easier and potentially faster to detect changes like blinks or eyelid position without needing complex analysis of the entire eye image.
What it does not cover
- Does not cover eye tracking systems that detect eyelid movement without first creating a differential image by comparing a current image to a reference image.
- Does not cover systems that determine eyelid data solely from analyzing individual pixels or columns, rather than combining differential intensity values in corresponding rows (Claim 1).
- Does not cover eye tracking methods that rely only on infrared reflections or pupil dilation without image differencing for eyelid detection.
- Does not cover systems that track the entire eye's movement without specifically processing images to extract eyelid location or blink data.
- Does not cover methods for determining eyelid data that do not involve a two-dimensional pixel array with differential intensity values.
Patent timeline
Application submitted to the patent office
Patent enters public domain
PatentBrief Score
Impact Score
Early stage
Citation count
6/40
Early citations
Claim breadth
15/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$62K – $200K
Midpoint $125K · 15.7 yr remaining · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
23 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Zachrisson, J., Rosell, M., Johansson, S., & WRANG, D. How Eye Trackers Detect Eyelid Movements and Blinks (U.S. Patent No. 20,230,004,223). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/20230004223/eye-tracking-system
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Eye Trackers Detect Eyelid Movements and Blinks cover?
This patent describes a method for eye tracking systems to precisely detect eyelid movements and blinks by comparing a current eye image to a reference image, then analyzing the differences in rows of pixels.
Who owns patent US 20230004223?
This patent is owned by Tobii AB.
When does this patent expire?
This patent is expected to expire on June 30, 2042, when the invention enters the public domain.
What is patent US 20230004223 cited by?
This patent has been cited by 1 later patents that build on its ideas.
What problem does this patent solve?
Accurate eyelid tracking is crucial for many applications, from understanding user attention in virtual reality to diagnosing neurological conditions. By precisely identifying eyelid positions and blinks, this technology can improve the reliability of eye-tracking data, making it more useful for both research and commercial products. This precision helps prevent false readings and provides richer information about a user's state.
What does this patent NOT cover?
Does not cover eye tracking systems that detect eyelid movement without first creating a differential image by comparing a current image to a reference image.
Patent monitoring