How Touchscreens Precisely Align Signals to Detect Your Touch
Apple's patent describes a way for touchscreens to adjust the timing of internal electrical signals so they perfectly match the signals coming from your finger, making touch detection more accurate.
Original patent title: “Individual channel phase delay scheme”
Apple's patent describes a way for touchscreens to adjust the timing of internal electrical signals so they perfectly match the signals coming from your finger, making touch detection more accurate. Granted to Apple Inc in 2013 with 57 claims and 13 forward citations, and it is expected to expire in 2027.
Coverage
What does this patent actually cover?
When you touch a screen, the electrical signal traveling through the sensor panel gets slightly delayed or shifted in phase. This patent describes a system that uses a 'demodulation signal' to track and cancel out that delay. By storing a specific 'phase delay value' in memory, the device can adjust its internal clock to match the incoming signal from the touch panel. This allows the device to cleanly mix, rectify, and filter the signal, effectively removing noise and ensuring the system knows exactly where and when you touched the screen.
The gap
What does this patent NOT cover?
- Does not cover general touch sensing methods that do not involve phase-matching demodulation.
- Does not cover software-based touch processing that occurs entirely after the analog-to-digital conversion stage.
- Does not cover non-capacitive touch technologies that do not rely on signal stimulation and traversal circuits.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
Instead of trying to force the incoming signal to be 'perfect,' the system dynamically adjusts its own internal reference signal to match the 'imperfect' incoming signal, effectively turning a timing error into a calibrated measurement.
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
iPhone capacitive touchscreens
iPad multi-touch displays
Modern smartphone proximity sensors
Why it matters
The bigger picture
This technology is essential for high-precision capacitive touchscreens, like those found in iPhones and iPads. By solving the problem of signal phase mismatch, it allows devices to maintain high sensitivity and noise immunity even as screens get larger or more complex. It represents a foundational piece of engineering that helped move touch interfaces from clunky, inaccurate prototypes to the responsive standard we use today.
Filed
January 3, 2007
Granted
July 23, 2013
Market context
Who's building on this
Companies in this space
Apple continues to refine these signal processing techniques in its custom silicon, such as the touch controllers integrated into the A-series chips. Other major display and controller manufacturers like Synaptics and Texas Instruments have developed similar signal-conditioning architectures to maintain signal integrity in high-resolution touch panels.
Market impact
This patent helped solidify the technical requirements for reliable multi-touch performance in mobile devices. By providing a robust method for noise suppression and signal demodulation, it enabled the mass-market adoption of highly responsive touch interfaces, effectively setting the bar for what users expect from a modern smartphone.
Claim 1 — Plain English
What this patent covers
When you touch a screen, the electrical signal traveling through the sensor panel gets slightly delayed or shifted in phase. This patent describes a system that uses a 'demodulation signal' to track and cancel out that delay. By storing a specific 'phase delay value' in memory, the device can adjust its internal clock to match the incoming signal from the touch panel. This allows the device to cleanly mix, rectify, and filter the signal, effectively removing noise and ensuring the system knows exactly where and when you touched the screen.
The clever bit
Instead of trying to force the incoming signal to be 'perfect,' the system dynamically adjusts its own internal reference signal to match the 'imperfect' incoming signal, effectively turning a timing error into a calibrated measurement.
What it does not cover
- Does not cover general touch sensing methods that do not involve phase-matching demodulation.
- Does not cover software-based touch processing that occurs entirely after the analog-to-digital conversion stage.
- Does not cover non-capacitive touch technologies that do not rely on signal stimulation and traversal circuits.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Strong
Citation count
23/40
Moderately cited
Claim breadth
20/20
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
$23K – $74K
Midpoint $46K · 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.
Claim text not yet imported for this patent
The original legal language
Original claims
57 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Krah, C. H. (2013). How Touchscreens Precisely Align Signals to Detect Your Touch (U.S. Patent No. 8,493,330). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/8493330/individual-channel-phase-delay-scheme
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 Touchscreens Precisely Align Signals to Detect Your Touch cover?
Apple's patent describes a way for touchscreens to adjust the timing of internal electrical signals so they perfectly match the signals coming from your finger, making touch detection more accurate.
Who owns patent US 8493330?
Apple Inc owns this patent, granted in 2013.
When does this patent expire?
This patent is expected to expire on January 3, 2027, when the invention enters the public domain.
What is patent US 8493330 cited by?
This patent has been cited by 13 later patents that build on its ideas.
What problem does this patent solve?
This technology is essential for high-precision capacitive touchscreens, like those found in iPhones and iPads. By solving the problem of signal phase mismatch, it allows devices to maintain high sensitivity and noise immunity even as screens get larger or more complex. It represents a foundational piece of engineering that helped move touch interfaces from clunky, inaccurate prototypes to the responsive standard we use today.
What does this patent NOT cover?
Does not cover general touch sensing methods that do not involve phase-matching demodulation.
Same assignee
More from Apple Inc
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