Capacitive Touch Data Compression via Run-Length Encoding

Solution Overview

Problem

Capacitive touch devices face issues with long data transmission times and high power consumption due to the large quantity of sensed data being transmitted from touch ICs to the processing unit, especially in all-points addressable capacitance sense technology.

Innovation Solution

A capacitive touch device and sensing method that compresses N-bit sensed data to L-bit data, where L is smaller than N, allowing for efficient transmission and processing, with the touch detection unit scanning and compressing data using methods like run-length encoding, and the processing unit decompressing and calculating touch coordinates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the touch ICs transmit the sensed data to the processing unit, then the coordinate of the touch can be calculated accurately, but the transmission time and power consumption increase due to the large quantity of sensed data

Engineering Contradiction:

Improvetouch coordinate calculation accuracyVSAvoiddata transmission time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential information from the sensed data by determining whether each pixel is a touch point or non-touch point, and transmitting only this binary information along with minimum/maximum capacitance values to the processing unit, thereby reducing transmission data volume while maintaining accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the data representation parameter from transmitting all sensed data values to transmitting compressed data with reduced precision (L-bit instead of N-bit), achieving a balance between transmission efficiency and calculation accuracy

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the touch ICs transmit the sensed data to the processing unit, then the coordinate of the touch can be calculated, but the power consumption increases due to the large amount of data transmission

Engineering Contradiction:

Improvetouch coordinate calculation accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential information from the sensed data by determining whether each pixel is a touch point or non-touch point, and transmitting only this binary information along with minimum/maximum capacitance values to the processing unit, thereby reducing transmission data volume while maintaining accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the data representation parameter from transmitting all sensed data values to transmitting compressed data with reduced precision (L-bit instead of N-bit), achieving a balance between transmission efficiency and calculation accuracy

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the touch ICs transmit the sensed data to the processing unit, then the coordinate of the touch can be calculated, but the memory capacity requirements increase due to the large quantity of sensed data

Engineering Contradiction:

Improvetouch coordinate calculation accuracyVSAvoidmemory capacity

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential information from the sensed data by determining whether each pixel is a touch point or non-touch point, and transmitting only this binary information along with minimum/maximum capacitance values to the processing unit, thereby reducing transmission data volume while maintaining accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the data representation parameter from transmitting all sensed data values to transmitting compressed data with reduced precision (L-bit instead of N-bit), achieving a balance between transmission efficiency and calculation accuracy

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9262026B2Capacitive touch device and sensing method thereof

Publication Date: 2016.02.16 SILICON INTEGRATED SYSTEMS CORP

AI summary

A capacitive touch device and a sensing method thereof are disclosed. The capacitive touch device includes a touch panel, at least one touch detection unit and a processing unit. The touch detection unit scans the touch panel, obtains an N-bit sensed data and compresses the N-bit sensed data to an L-bit sensed data. The processing unit receives the L-bit sensed data, decompresses the L-bit sensed data to the N-bit sensed data and calculates a coordinate of a touch according to the N-bit sensed data. The present invention is capable of decreasing the time for transmitting the sensed data, the power consumption and the requirements for the memory capacity of the touch detection unit and the memory capacity of the processing unit.