Sensor Layer Parasitic Capacitance Reduction

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Solution Overview

Problem

Existing electronic devices face challenges in accurately detecting inputs from both touch and input devices due to high parasitic capacitance, which can lead to reduced detection sensitivity and incorrect coordinate detection.

Innovation Solution

The electronic device incorporates a sensor layer with a modified electrode structure, where the first and second sensing electrodes are electrically separated, and the sensing patterns are arranged to reduce parasitic capacitance, allowing for improved detection sensitivity and accuracy in coordinate detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor layer uses a conventional electrode structure, then the device can detect touch inputs, but high parasitic capacitance reduces detection sensitivity and coordinate accuracy

Engineering Contradiction:
Improvecoordinate detection accuracyVSAvoidparasitic capacitance
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensor layer is divided into multiple sensing regions with separate first and second sensing electrodes in each region. This segmentation allows independent control and optimization of each sensing region, reducing parasitic capacitance effects and improving coordinate detection accuracy for touch and input device detection

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different electrode configurations are applied to different sensing regions based on their specific requirements. The first and second sensing electrodes are arranged with specific spacing and overlapping patterns in different regions to optimize local detection characteristics and minimize parasitic capacitance in each area

Inventive Principle:
Principle #3Local quality

2Measurement precision

If additional sensor layers are added to improve detection accuracy, then coordinate detection sensitivity increases, but device thickness increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoiddevice thickness
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The sensor layer combines multiple sensing functions into a single layer by implementing both first and second sensing electrodes that can detect different types of inputs (touch and input devices) simultaneously. This merging approach achieves high detection sensitivity without requiring multiple separate sensor layers, thereby maintaining thin device profile

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the electrode structure is modified to reduce parasitic capacitance, then detection sensitivity improves, but electrode structure complexity increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidelectrode structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the parasitic capacitance problem by carefully designing the electrode structure to minimize overlapping and unwanted capacitance effects. The first and second sensing electrodes are positioned and dimensioned to achieve low parasitic capacitance while maintaining detection sensitivity, avoiding the need for additional complex compensation structures

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration enhances the accuracy of coordinate detection and increases the sensitivity of the sensor layer, enabling effective detection of both touch and input device coordinates without the need for additional layers, thus reducing the device's thickness and increasing flexibility.

Implementation Method 1

The electronic device may use electromagnetic resonance (EMR) or active electrostatic (AES) to recognize coordinate information of a pen

Methodology Applied
Scientific EffectElectromagnetic resonance (EMR): Resonance

Implementation Method 2

The electronic device may use electromagnetic resonance (EMR) or active electrostatic (AES) to recognize coordinate information of a pen

Methodology Applied
Scientific EffectActive electrostatic (AES): Electrostatics

Implementation Method 3

The stylus includes a housing having an end in an elongated direction of the housing, a conductive tip disposed at least partially extended from the end of the housing, an electrode disposed around the conductive tip and configured to at least partially expose the conductive tip, and a signal transmit drive circuit configured to provide a signal. Control is performed to form an electrical connection between the electrode and a ground and an electrical connection between the electrode and the signal transmit drive circuit when the elongated stylus is activated for capacitive coupling with the sensor array

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3929711B1Electronic device
Publication Date: 2023.09.06 SAMSUNG DISPLAY CO LTD
  • EP3929711B1 patent drawingFigure 1
  • EP3929711B1 patent drawingFigure 2A
  • EP3929711B1 patent drawingFigure 2B

AI summary

An electronic device, includes: a sensor layer detecting a touch input and an input-device input; and a sensor control circuit providing the sensor layer with a signal and receiving a detection signal from the sensor layer, wherein the sensor layer includes: a first electrode extending along a first direction; a second electrode extending along the first direction; a first cross electrode extending along a second direction intersecting the first direction; and a second cross electrode extending along the second direction, wherein the sensor control circuit detects the touch input based on a variation in mutual capacitance between the first electrode and the first cross electrode, and the sensor control circuit detects the input-device input based on a variation in capacitance of at least one selected from the first electrode, the second electrode, the first cross electrode, and the second cross electrode.