How Your Phone Knows When It's Against Your Ear
This Apple patent describes how a phone uses both a proximity sensor and an ambient light sensor to accurately detect when it's held to your ear, preventing accidental screen touches during calls.
Original patent title: “Using ambient light sensor to augment proximity sensor output”
This Apple patent describes how a phone uses both a proximity sensor and an ambient light sensor to accurately detect when it's held to your ear, preventing accidental screen touches during calls. Granted to Apple Inc in 2011 with 28 claims and 368 forward citations.
Key facts
Coverage
What does this patent actually cover?
The patent describes a method where a phone first uses a proximity sensor to estimate the distance to an object, like a user's ear (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). Simultaneously, it receives light intensity information from an ambient light sensor (ALS) (Claim 1). If the ALS output indicates that the proximity sensor's initial distance estimate is incorrect, the phone's data processing system then uses the ALS data to correct that estimated distance (Claim 1). This correction can change the device's understanding of an object's proximity from 'far away' to 'close' (Claim 3). Both sensors are typically located near the phone's earpiece (Claim 2). For example, if you bring your phone to your ear, the proximity sensor might detect something, but the ALS would also detect a sudden drop in ambient light. The phone uses this combined information to confirm your ear is truly close, then automatically turns off the display backlight or disables touch input to prevent accidental actions (Claim 7).
The gap
What does this patent NOT cover?
- Proximity sensing systems that rely solely on a single sensor without incorporating correction from another sensor type.
- Using an ambient light sensor only for adjusting screen brightness, not for refining proximity detection.
- Proximity detection where the ambient light sensor's output does not actively correct an initial distance estimate from a proximity sensor.
- Devices where the proximity sensor and ambient light sensor are not positioned adjacent to the earpiece.
- Proximity detection methods that do not involve receiving an 'intensity level output' from both a proximity sensor and an ambient light sensor.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in using the ambient light sensor not just for its primary function of adjusting screen brightness, but specifically to verify and correct the initial, potentially inaccurate, distance estimate from the proximity sensor, making the overall proximity detection system much more robust.
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
iPhone (all models with earpieces)
Most modern smartphones
Why it matters
The bigger picture
This technology is fundamental to the user experience of modern smartphones. It prevents common frustrations like accidentally muting calls or launching apps when the phone is held against the face. By combining data from two different sensors, it makes proximity detection more accurate and reliable, especially in various lighting conditions, which is critical for seamless phone calls.
Filed
January 7, 2007
Granted
June 7, 2011
Market context
Who's building on this
Companies in this space
Apple Inc., the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, continues to integrate and refine this type of sensor fusion in its iPhone product line. Other major smartphone manufacturers, including Samsung and Google, also employ similar techniques to enhance the reliability of proximity detection and improve the user experience during phone calls.
Market impact
This patent significantly improved the reliability of smartphone operation during calls, particularly for early touchscreen devices. It helped establish a standard for how phones manage their displays and touch inputs when held to the face, preventing accidental interactions and contributing to the widespread adoption and acceptance of all-screen smartphone designs.
Claim 1 — Plain English
What this patent covers
The patent describes a method where a phone first uses a proximity sensor to estimate the distance to an object, like a user's ear (Claim 1). Simultaneously, it receives light intensity information from an ambient light sensor (ALS) (Claim 1). If the ALS output indicates that the proximity sensor's initial distance estimate is incorrect, the phone's data processing system then uses the ALS data to correct that estimated distance (Claim 1). This correction can change the device's understanding of an object's proximity from 'far away' to 'close' (Claim 3). Both sensors are typically located near the phone's earpiece (Claim 2). For example, if you bring your phone to your ear, the proximity sensor might detect something, but the ALS would also detect a sudden drop in ambient light. The phone uses this combined information to confirm your ear is truly close, then automatically turns off the display backlight or disables touch input to prevent accidental actions (Claim 7).
The clever bit
The innovation lies in using the ambient light sensor not just for its primary function of adjusting screen brightness, but specifically to verify and correct the initial, potentially inaccurate, distance estimate from the proximity sensor, making the overall proximity detection system much more robust.
What it does not cover
- Proximity sensing systems that rely solely on a single sensor without incorporating correction from another sensor type.
- Using an ambient light sensor only for adjusting screen brightness, not for refining proximity detection.
- Proximity detection where the ambient light sensor's output does not actively correct an initial distance estimate from a proximity sensor.
- Devices where the proximity sensor and ambient light sensor are not positioned adjacent to the earpiece.
- Proximity detection methods that do not involve receiving an 'intensity level output' from both a proximity sensor and an ambient light sensor.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
High impact
Citation count
40/40
Highly cited
Claim breadth
19/20
Very broad protection
Recency
5/20
Granted 10–20 years ago
Assignee scale
20/20
Major company or institution
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
$117K – $374K
Midpoint $234K · expired or expiring · 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.
The original legal language
Original claims
28 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Westerman, W. C., Hotelling, S. P., Yepez, R. G., & Herz, S. M. (2011). How Your Phone Knows When It's Against Your Ear (U.S. Patent No. 7,957,762). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/7957762/ios-app-store
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 Your Phone Knows When It's Against Your Ear cover?
This Apple patent describes how a phone uses both a proximity sensor and an ambient light sensor to accurately detect when it's held to your ear, preventing accidental screen touches during calls.
Who owns patent US 7957762?
Apple Inc owns this patent, granted in 2011.
When does this patent expire?
This patent is expected to expire on June 7, 2031, when the invention enters the public domain.
What is patent US 7957762 cited by?
This patent has been cited by 368 later patents that build on its ideas.
What problem does this patent solve?
This technology is fundamental to the user experience of modern smartphones. It prevents common frustrations like accidentally muting calls or launching apps when the phone is held against the face. By combining data from two different sensors, it makes proximity detection more accurate and reliable, especially in various lighting conditions, which is critical for seamless phone calls.
What does this patent NOT cover?
Proximity sensing systems that rely solely on a single sensor without incorporating correction from another sensor type.
Same assignee
More from Apple Inc
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