# 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. - **Patent:** US 8493330 - **Original title:** Individual channel phase delay scheme - **Owner:** Apple Inc - **Granted:** 2013 - **Status:** Active - **Times cited:** 13 - **Field:** consumer_electronics, semiconductors ## What it does 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. ## 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. ## 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. ## Real-world examples 1. iPhone capacitive touchscreens 2. iPad multi-touch displays 3. Modern smartphone proximity sensors ## Why it matters 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. ## 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. **Full plain-English explainer:** https://patentbrief.org/patent/us/8493330/individual-channel-phase-delay-scheme **Original patent:** https://patents.google.com/patent/US8493330 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Touchscreens Save Battery by Sleeping Between Touches](https://patentbrief.org/patent/us/8125456/multi-touch-capacitive-scanning) — A power-saving method for touchscreens that puts the main processor to sleep when not in use and wakes it up only when a touch is detected. - [How Touchscreens Predict Where Your Finger Will Land Before You Touch](https://patentbrief.org/patent/us/10564770/airpods-wireless-earbuds) — Apple's patent describes a touch controller that tracks an object's path through the air to predict where it will land on a screen before it actually makes physical contact. - [How Multi-Touch Screens Track Multiple Fingers at Once](https://patentbrief.org/patent/us/7663607/multipoint-touchscreen) — Apple's 2010 patent describes a touch screen that uses two layers of transparent conductive lines to detect several fingers touching the screen simultaneously. - [How Touchscreens Tell Real Touches From False Ghost Touches](https://patentbrief.org/patent/us/8619056/ghost-resolution-for-a-capacitive-touch-panel) — A method for capacitive touchscreens to distinguish between actual finger presses and false ghost signals that occur when multiple points are touched simultaneously. - [How Multi-Touch Gestures Like Pinch-to-Zoom Work on Smartphones](https://patentbrief.org/patent/us/7812826/iphone-software-keyboard) — Apple's patent on using two-finger gestures to manipulate images and objects on a touchscreen, allowing for smooth zooming and rotation even if you lift your fingers briefly.