Stylus Touch Screen Using Wireless Signal Magnitude Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current touch screen devices struggle to accurately recognize and locate stylus touches due to the larger capacitive effects of human fingers, leading to potential customer dissatisfaction and reduced sales.

Innovation Solution

A touch screen device equipped with conductors that receive wireless signals from a stylus, featuring an amplifier circuit, analog-to-digital converter, and processor using an algorithmic transform to determine the stylus's location based on signal magnitudes, allowing precise detection and manipulation of content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If capacitive touch sensors are used to detect finger touches, then the touch screen can recognize finger inputs, but the larger capacitive effect of fingers reduces measurement precision for stylus touches

Engineering Contradiction:

Improvetouch input recognitionVSAvoidstylus touch location accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces wireless signals as an intermediary mechanism between the stylus and the touch screen. Instead of relying on the capacitive effect of the stylus tip (which is similar to finger touch), the stylus transmits wireless signals that are received by conductors on the touch screen. This intermediary wireless communication method allows the system to distinguish stylus inputs from finger inputs and achieve precise location detection without being affected by the capacitive interference that plagues traditional capacitive touch screens.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If traditional capacitive touch detection is used, then the system can handle both finger and stylus inputs, but it cannot accurately distinguish or locate stylus touches

Engineering Contradiction:

Improvedual input supportVSAvoidstylus touch detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/electrical capacitive detection system with an electromagnetic wireless signal transmission and reception system. The stylus acts as a wireless transmitter, and the touch screen contains conductors that function as wireless receivers. This substitution allows the system to maintain versatility (supporting both finger and stylus inputs) while achieving accurate stylus location detection through signal strength analysis, eliminating the ambiguity inherent in capacitive-based stylus detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If wireless signal reception is implemented across the entire touch screen, then stylus location can be accurately determined, but device complexity increases

Engineering Contradiction:

Improvestylus location accuracyVSAvoidconductor and circuit configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the touch screen into multiple segments, each with its own conductor that receives wireless signals from the stylus. By segmenting the detection area and assigning specific conductors to specific regions, the system can determine stylus location by identifying which segment receives the strongest signal. This segmentation approach enables accurate location detection while keeping the complexity of individual conductor circuits manageable, as each conductor only needs to process signals within its local segment.

Inventive Principle:

Principle #1Segmentation

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

Enables accurate detection and location of stylus touches on the touch screen, enhancing user interaction precision and customer satisfaction by distinguishing stylus inputs from finger inputs.

Implementation Method 1

The stylus is equipped with a transmitter to emit wireless signals, and the touch screen includes conductors that can receive the wireless signals

Methodology Applied

Scientific EffectElectromagnetic radiation:

Implementation Method 2

An amplifier circuit filters and amplifies the wireless signals, as received by the conductors

Methodology Applied

Scientific EffectSignal amplification:

Implementation Method 3

An analog-to-digital converter (ADC) digitizes the filtered and amplified wireless signals

Methodology Applied

Scientific EffectAnalog-to-digital conversion:

Data Source

PatentUS9454272B2Touch screen for stylus emitting wireless signals

Publication Date: 2016.09.27 STMICROELECTRONICS INT NV

AI summary

A touch screen device is configured with rows of conductors capable of receiving wireless signals from a stylus. When the stylus touches the touch screen, the stylus emits multiple wireless signals in different directions. The conductors receiving the emitted wireless signals provide the signals to circuitry that filters, amplifies, and digitizes the wireless signals, as received at each conductor. The magnitude of each conductor's received wireless signal is computed, and the computed magnitudes are used to determine the location of the stylus on the touch screen surface. The stylus is assumed to be closer to conductors receiving stronger signals than those receiving weaker signals.