Touch Sensor Scanning During Display Blanking Intervals

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Solution Overview

Problem

Conventional touch-screen input/output devices experience interference issues during active display scan times, leading to noise that affects the accuracy of touch event and position sensing, requiring substantial filtering or increased voltage to read touch sensors accurately.

Innovation Solution

Scanning the touch sensor array during vertical and horizontal blanking intervals, where pixel values are not being driven onto the display, to minimize interference and enhance accuracy, using a synchronization module to interleave touch sensor scan cycles with video display signal blanking periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If touch sensor scanning is performed during active display scan times, then touch sensing can be continuously monitored, but noise and interference increase affecting sensing accuracy

Engineering Contradiction:

Improvetouch sensing continuityVSAvoidtouch sensing accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the display scanning process into active scan periods and blanking intervals, allocating touch sensor scanning exclusively to the blanking intervals. This temporal segmentation allows continuous touch monitoring without interfering with active display scanning, thereby maintaining both productivity and measurement precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic touch sensor scanning synchronized with the display's vertical and horizontal blanking intervals. By performing touch scans periodically during these natural pauses in display operation, the system maintains continuous touch sensing capability while avoiding noise interference from active scanning periods.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If substantial filtering or increased voltage is used to read touch sensors during active scan times, then touch sensing accuracy can be maintained, but power consumption and device complexity increase

Engineering Contradiction:

Improvetouch sensing accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs touch sensor scanning during blanking intervals before the next active display scan begins. This preliminary action allows touch data to be collected in advance during low-interference periods, eliminating the need for power-intensive filtering or voltage boosting that would be required if scanning occurred during active periods.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the otherwise wasted blanking intervals (periods when display pixels are not being updated) into beneficial scanning opportunities. By utilizing these previously idle time periods for touch sensor scanning, the system achieves accurate touch detection without the power consumption penalties associated with filtering or voltage enhancement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If dedicated processing is allocated for touch sensor scanning, then touch event detection accuracy improves, but device costs and power consumption increase

Engineering Contradiction:

Improvetouch event detection accuracyVSAvoidprocessing architecture

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a synchronization module that coordinates display scanning and touch sensor scanning operations within the existing display control architecture. This multi-functional approach allows the same processing resources to handle both display output and touch sensing without requiring dedicated processing hardware, thereby reducing device complexity while maintaining detection accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the touch sensor scanning function with the display scanning operations by utilizing the display's blanking intervals for touch data acquisition. This consolidation allows the system to achieve accurate touch event detection without adding separate dedicated processing pathways, thus reducing overall device complexity and power consumption.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9746954B2Touch-screen input/output device touch sensing techniques

Publication Date: 2017.08.29 NVIDIA CORP

AI summary

A touch-screen input/output device including a touch sensor, a display, a display control module, a touch sensor control module and a synchronizer module. The touch sensor is overlaid on a display. The display control module is communicatively coupled to the display and converts video data into a serial bit stream video display signal include one or more blanking intervals. The touch sensor control module is communicatively coupled to the touch sensor and determines touch events and location of the touch event on the touch sensor during one or more touch sensor scan cycles. The synchronizer module is communicatively coupled between the display control module and the touch sensor control module, and interleaves the one or more touch sensor scan cycles with the one or more blanking intervals of the video display signal.