Touch Sensing System Temperature Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Capacitive touchscreens embedded in display panels experience reduced touch sensitivity due to temperature changes, leading to detection errors as capacitance values fluctuate without actual touch input.

Innovation Solution

A touch sensing system that includes a charge distributor, pre-amplifier, and analog-to-digital converter (ADC) with a temperature compensating device, which adjusts reference voltages and capacitance based on real-time temperature measurements to maintain consistent touch data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the capacitance of capacitor Cfb of pre-amplifier is increased or input range of ADC is increased for temperature compensation, then touch sensitivity is improved, but area of capacitor and power consumption of ADC increase

Engineering Contradiction:

Improvetouch sensitivityVSAvoidpower consumption of ADC

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters of existing components (capacitance value of Cfb, input range of ADC) to achieve temperature compensation. By adjusting these parameters based on temperature conditions, the system maintains touch sensitivity without requiring additional hardware or excessive power consumption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic adjustment capability where the capacitance of Cfb and input range of ADC are not fixed but can be modified according to temperature conditions. This dynamic adaptation allows the system to optimize performance across different thermal environments without permanent hardware changes.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If the capacitance of capacitor Cfb of pre-amplifier is increased or input range of ADC is increased for temperature compensation, then touch sensitivity is improved, but area of capacitor increases

Engineering Contradiction:

Improvetouch sensitivityVSAvoidarea of capacitor

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

Instead of increasing physical capacitor area, the patent modifies the capacitance parameter through electrical means (adjusting Cfb value and ADC input range). This parameter-based approach achieves compensation without proportional increase in physical footprint.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces physical expansion (increasing capacitor area) with electrical parameter adjustment. By using electrical means to modify capacitance values and voltage ranges, the system achieves the same compensation effect without mechanical growth in component size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Prevents changes in touch data due to temperature fluctuations, thereby enhancing touch sensitivity and accuracy by compensating for temperature-induced capacitance changes.

Implementation Method 1

a temperature sensor, and a temperature compensating device which varies one or more of a first reference voltage supplied to the charge distributor, a second reference voltage supplied to the pre-amplifier, and the capacitance of the charge distributor in response to temperature data from the temperature sensor

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 2

The charge distributor is connected between the touch sensor and a pre-amplifier. The pre-amplifier receives charge from a touch sensor

Methodology Applied

Scientific EffectCharge distribution: Electrostatics

Implementation Method 3

The pre-amplifier receives charge from a touch sensor, amplifies the charge, and outputs a voltage signal

Methodology Applied

Scientific EffectSignal amplification:

Implementation Method 4

The ADC converts an analog voltage output from the pre-amplifier to digital data to generate touch raw data

Methodology Applied

Scientific EffectAnalog-to-digital conversion:

Implementation Method 5

the temperature compensating device varies one or more of a first reference voltage supplied to the charge distributor, a second reference voltage supplied to the pre-amplifier, and the capacitance of the charge distributor, in response to temperature data from a temperature sensor

Methodology Applied

Scientific EffectTemperature compensation:

Data Source

PatentUS9857914B2Touch sensing system

Publication Date: 2018.01.02 LG DISPLAY CO LTD

AI summary

A touch sensing system includes a charge distributor, a pre-amplifier, an analog-to-digital converter (ADC), and a temperature compensating device. The temperature compensating device varies one or more of a first reference voltage supplied to the charge distributor, a second reference voltage supplied to the pre-amplifier, and the capacitance of the charge distributor, in response to temperature data from a temperature sensor.