Multi-touch Sensing with Simultaneous Drive Line Stimulation
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Solution Overview
Problem
Conventional touch and proximity-based input systems for electronic devices are inefficient in recognizing multiple simultaneous touch and hover events due to the sequential stimulation of drive lines, which leads to increased power consumption and time requirements.
Innovation Solution
Simultaneously stimulating multiple drive lines with unique drive signals having predetermined phase and frequency relationships to derive touch information from sense signals, allowing for simultaneous detection of touch and proximity events across a touch-sensitive surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drive lines are stimulated sequentially one at a time, then the system can detect touch events, but power consumption increases and processing time extends
Solution Approach 1:
The patent segments the touch sensing process into two distinct phases: a coarse scan phase that quickly checks multiple drive lines for touch presence, and a fine scan phase that performs detailed analysis only on lines where touches are detected. This segmentation eliminates the need to perform fine scans on all drive lines, thereby reducing processing time while maintaining detection accuracy.
Solution Approach 2:
The patent applies partial action by performing comprehensive fine scanning only on a subset of drive lines where touches are detected during the coarse scan phase. Rather than scanning all drive lines with equal detail, the system applies detailed scanning only where necessary, reducing overall processing time while maintaining measurement precision for actual touch events.
2Measurement precision
If drive lines are stimulated sequentially one at a time, then the system can detect touch events, but power consumption increases
Solution Approach 1:
The patent segments the touch sensing operation into coarse scan and fine scan phases, where the power-intensive fine scan is executed only on drive lines where touches are detected. This segmentation significantly reduces overall power consumption compared to performing fine scans on all drive lines sequentially, while maintaining detection accuracy through the two-phase approach.
Solution Approach 2:
The system applies partial scanning by performing detailed, power-consuming fine scans only on drive lines where touches are detected during the coarse phase. This selective application of detailed scanning reduces total power consumption while maintaining measurement precision for actual touch events, avoiding wasteful energy expenditure on lines without touches.
3Productivity
If multiple drive lines are stimulated simultaneously, then processing time and power consumption are reduced, but signal interference may occur
Solution Approach 1:
The patent segments the scanning process into coarse and fine phases, with the coarse phase using simultaneous stimulation of multiple drive lines to quickly identify touch locations. This segmentation allows simultaneous stimulation to be used safely in the coarse phase where signal interference is less critical, while the fine phase processes only the identified touch locations, thereby improving productivity while managing signal interference through phase-based segmentation.
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
This approach reduces power consumption and processing time by eliminating unnecessary fine scans, enabling efficient recognition of multiple touch attributes and gestures on touch-sensitive surfaces, such as touch screens and tablets.
Implementation Method 1
Each sensing point can be located at or near a crossing of a drive line and a sense line
Data Source
AI summary
Multi-touch touch-sensing devices and methods are described herein. The touch sensing devices can include multiple sense points, each located at a crossing of a drive line and a sense line. In some embodiments, multiple drive lines may be simultaneously or nearly simultaneously stimulated with drive signals having unique characteristics, such as phase or frequency. A sense signal can occur on each sense line that can be related to the drive signals by an amount of touch present at sense points corresponding to the stimulated drive lines and the sense line. By using processing techniques based on the unique drive signals, an amount of touch corresponding to each sense point can be extracted from the sense signal. The touch sensing methods and devices can be incorporated into interfaces for a variety of electronic devices such as a desktop, tablet, notebook, and handheld computers, personal digital assistants, media players, and mobile telephones.