How Optical Sensors Find Multiple Touches on a Screen
This patent describes a system that uses at least two pairs of light sensors and clever math to accurately figure out where multiple fingers are touching a screen, even when shadows overlap.
Original patent title: “Stereo Optical Sensors for Resolving Multi-Touch in a Touch Detection System”
This patent describes a system that uses at least two pairs of light sensors and clever math to accurately figure out where multiple fingers are touching a screen, even when shadows overlap. Owned by Individual with 28 claims and 34 forward citations, and it is expected to expire in 2029.
Coverage
What does this patent actually cover?
The system uses light emitters to shine energy across a touch area. When a finger touches the screen, it casts shadows. A first pair of optical sensors detects these shadows and, using triangulation, figures out a "first set of potential points" where touches might be (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). A second pair of optical sensors does the same, creating a "second set of potential points" (Claim 1). A computer then compares these two sets, looking for pairs of potential points that are very close to each other. The pairs with the shortest distances are identified as the actual "true touch points" (Claim 1). For example, if two fingers touch a screen, each pair of sensors might initially see several possible touch locations, but only the actual touch points will be consistently identified by both sensor pairs as very close together.
The gap
What does this patent NOT cover?
- Touch detection systems that rely on electrical properties, like capacitive touchscreens.
- Single-touch systems, as the claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → specifically address "multitouch scenarios" and "multiple true touch points" (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Systems that use only one pair of optical sensors for touch detection.
- Touchscreens that do not use optical emitters and sensors to detect shadows.
- Methods for resolving multitouch that do not involve comparing potential points from at least two distinct sensor pairs and calculating distances.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The core innovation is using multiple stereo pairs of optical sensors to generate two independent sets of potential touch points. By comparing these two sets and identifying the closest matches, the system efficiently filters out "ghost" touches or ambiguities that arise from shadows, significantly reducing the computational effort compared to evaluating all possible combinations from a single, larger set of potential points.
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
Large interactive displays
Digital whiteboards
Some industrial control panels
Certain types of touch tables
Why it matters
The bigger picture
Multi-touch technology is fundamental to modern smartphones, tablets, and interactive displays. This patent contributes to the underlying methods for accurately sensing multiple simultaneous inputs, which is critical for gestures like pinch-to-zoom or two-finger scrolling. While many multi-touch systems are capacitive, optical methods offer alternatives for larger displays or specific environments.
Filed
September 29, 2009
Market context
Who's building on this
Companies in this space
Companies developing large-format interactive displays, such as those used in education, retail, and corporate meeting rooms, might utilize or adapt optical multi-touch technologies. Manufacturers of digital whiteboards and interactive kiosks are also active in this space.
Market impact
This type of optical multi-touch technology enabled the development of larger, more robust interactive surfaces where capacitive touch might be impractical or too costly. It provided an alternative sensing mechanism, particularly for applications requiring durable surfaces or interaction with gloved hands, expanding the range of environments where multi-touch could be deployed.
Claim 1 — Plain English
What this patent covers
The system uses light emitters to shine energy across a touch area. When a finger touches the screen, it casts shadows. A first pair of optical sensors detects these shadows and, using triangulation, figures out a "first set of potential points" where touches might be (Claim 1). A second pair of optical sensors does the same, creating a "second set of potential points" (Claim 1). A computer then compares these two sets, looking for pairs of potential points that are very close to each other. The pairs with the shortest distances are identified as the actual "true touch points" (Claim 1). For example, if two fingers touch a screen, each pair of sensors might initially see several possible touch locations, but only the actual touch points will be consistently identified by both sensor pairs as very close together.
The clever bit
The core innovation is using multiple stereo pairs of optical sensors to generate two independent sets of potential touch points. By comparing these two sets and identifying the closest matches, the system efficiently filters out "ghost" touches or ambiguities that arise from shadows, significantly reducing the computational effort compared to evaluating all possible combinations from a single, larger set of potential points.
What it does not cover
- Touch detection systems that rely on electrical properties, like capacitive touchscreens.
- Single-touch systems, as the claims specifically address "multitouch scenarios" and "multiple true touch points" (Claim 1).
- Systems that use only one pair of optical sensors for touch detection.
- Touchscreens that do not use optical emitters and sensors to detect shadows.
- Methods for resolving multitouch that do not involve comparing potential points from at least two distinct sensor pairs and calculating distances.
Patent timeline
Application submitted to the patent office
Patent enters public domain
PatentBrief Score
Impact Score
Moderate
Citation count
31/40
Moderately cited
Claim breadth
19/20
Very broad protection
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
$94K – $300K
Midpoint $187K · 2.9 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
28 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Newton, J. D. How Optical Sensors Find Multiple Touches on a Screen (U.S. Patent No. 20,110,205,189). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/20110205189/stereo-optical-sensors-for-resolving-multi-touch-in-a-touch-detection-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 Optical Sensors Find Multiple Touches on a Screen cover?
This patent describes a system that uses at least two pairs of light sensors and clever math to accurately figure out where multiple fingers are touching a screen, even when shadows overlap.
Who owns patent US 20110205189?
This patent is owned by Individual.
When does this patent expire?
This patent is expected to expire on September 29, 2029, when the invention enters the public domain.
What is patent US 20110205189 cited by?
This patent has been cited by 34 later patents that build on its ideas.
What problem does this patent solve?
Multi-touch technology is fundamental to modern smartphones, tablets, and interactive displays. This patent contributes to the underlying methods for accurately sensing multiple simultaneous inputs, which is critical for gestures like pinch-to-zoom or two-finger scrolling. While many multi-touch systems are capacitive, optical methods offer alternatives for larger displays or specific environments.
What does this patent NOT cover?
Touch detection systems that rely on electrical properties, like capacitive touchscreens.
Same assignee
More from Individual
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