Electronic Display Quiet Periods for Sensor Accuracy

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Solution Overview

Problem

Electronic displays can cause electromagnetic interference that affects touch sensor functionality and distort ambient light sensing, leading to image artifacts and reduced sensor accuracy.

Innovation Solution

Implementing a quiet period during which the electronic display stops operating, allowing touch sensors to function without interference and ambient light sensors to accurately measure ambient light, coupled with strategies to mitigate image artifacts such as applying off-bias voltage, precharge periods, and strategic reset voltages to manage parasitic capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electronic display operates continuously to display images, then the display functionality is maintained, but electromagnetic interference affects touch sensor functionality and distorts ambient light sensing

Engineering Contradiction:

Improvesensor accuracyVSAvoiddisplay operation continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic quiet periods during which the display turns off to allow sensors to operate without electromagnetic interference. The display alternates between active display periods and inactive quiet periods, creating a periodic operation pattern that resolves the contradiction between continuous display operation and accurate sensor functionality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The display operation is segmented into distinct active periods and quiet periods. During active periods, the display operates normally; during quiet periods, the display turns off to enable accurate sensor operation. This segmentation allows both display functionality and sensor accuracy to be maintained in different time segments.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the display turns off during quiet periods to reduce electromagnetic interference, then sensor accuracy improves, but image artifacts appear due to parasitic capacitance discharge

Engineering Contradiction:

Improveambient light sensing accuracyVSAvoidimage artifacts

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by using precharge periods before quiet periods and reset periods after quiet periods. The precharge period prepares the pixel circuits by charging capacitors to appropriate levels before the display turns off, preventing unwanted discharge during the quiet period. The reset period afterward clears any residual charge that could cause image artifacts, thus preventing harmful effects before they occur.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The precharge period performs preliminary action by charging the pixel circuit capacitors to the correct voltage levels before the quiet period begins. This preliminary charging ensures that when the display turns off, the capacitors are properly prepared and will not discharge through the pixel circuits, preventing image artifacts while still allowing accurate sensor operation during the quiet period.

Inventive Principle:

Principle #10Preliminary action

3Illumination intensity

If precharge periods are extended to prevent dimness in rows activated after quiet periods, then brightness uniformity improves, but the time available for accurate sensor measurement decreases

Engineering Contradiction:

Improvedisplay brightness uniformityVSAvoidsensor measurement time

Core Design Contradiction:

Illumination intensityVSLoss of time

Solution Approach 1:

The patent applies partial action by providing precharge periods only for specific rows that will be activated after quiet periods, rather than charging all rows continuously. The precharge is applied selectively and partially during the quiet period for rows needing it, achieving brightness uniformity without unnecessarily extending the total precharge time that would reduce sensor measurement opportunities.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances coexistence of electronic displays with sensors by reducing electromagnetic interference and image artifacts, ensuring seamless operation and accurate sensor readings.

Implementation Method 1

the light from the electronic display may be detected by the ambient light sensor and may offer a distorted view of the ambient light

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Implementation Method 2

operating the electronic display may cause electromagnetic interference that may affect the touch sensor functionality

Methodology Applied

Scientific EffectElectromagnetic interference: Electromagnetic Induction

Implementation Method 3

to prevent undesired light emission due to excess charge from a parasitic capacitance after a quiet period

Methodology Applied

Scientific EffectParasitic capacitance: Capacitance

Data Source

PatentUS12387670B2Electronic display timing to mitigate image artifacts or manage sensor coexistence

Publication Date: 2025.08.12 APPLE INC

AI summary

Electronic devices, displays, and methods are provided for operating an electronic display in coexistence with sensors that could be adversely impacted by the operation of the electronic display. An electronic device may include an electronic display and a sensor. The electronic display may display image content by light emission during an emission period and periodically enter a quiet period in which the light emission of the electronic display is turned off. The sensor may perform sensing operations during the quiet period without interference from the operation of the electronic display.