Multi-functional Stylus with Optical Sensor and Pointing Stick

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Solution Overview

Problem

Existing active styluses are limited in functionality, failing to replace conventional mice due to obstructive operation on touch-screens and limited cursor control, especially with screen size and resolution constraints.

Innovation Solution

Integrating a pointing stick or optical sensor into the stylus, allowing input via an alternate wireless channel (Bluetooth, NFC, RF) independent of the electrostatic touch-screen channel, enabling seamless switching between modes based on stylus proximity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stylus operates by moving the writing tip over the touch-screen, then input can be provided to the device, but the user's view is obstructed and cursor control is limited by screen size and resolution

Engineering Contradiction:
Improvecursor controlVSAvoiduser's view
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent introduces an optical sensor as an intermediary device that enables cursor control without requiring the stylus tip to be in direct contact with or proximity to the touch-screen. The optical sensor detects surface features and calculates cursor position based on sensor movement relative to the surface, acting as a mediator between the stylus and the display surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/electrostatic interaction system (where the stylus tip must physically interact with the touch-screen surface) with an optical sensing system. The optical sensor uses light reflection and image processing to detect position and movement, substituting the mechanical contact-based input method with an optical-based method that does not obstruct the user's view.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the stylus uses the electrostatic channel of the touch-screen for transmission, then input can be provided, but additional input methods such as air mouse and joystick are not available

Engineering Contradiction:
Improveinput methodsVSAvoidtransmission channel
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the stylus multi-functional by integrating both the electrostatic transmission capability (for touch-screen interaction) and optical sensing capability (for mouse-like control). The optical sensor can operate independently of the touch-screen, enabling the stylus to function as a mouse, air mouse, or joystick in addition to its original touch input function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the input functionality into two independent systems: the electrostatic channel for touch-screen interaction and the optical sensor channel for surface-based cursor control. This segmentation allows each system to operate independently, providing versatility in input methods without requiring a single complex transmission channel to handle all functions.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If the writing tip is positioned close to the digitizer sensor, then signal detection is improved, but the user's view of the screen is obstructed

Engineering Contradiction:
Improvesignal detectionVSAvoidscreen visibility
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The optical sensor acts as an intermediary that enables precise measurement of cursor position without requiring the stylus tip to be close to the screen. By detecting reflected light patterns and calculating position based on sensor movement relative to surface features, the system achieves high measurement precision while maintaining visual clarity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances cursor control and functionality by providing additional input methods, such as air mouse and joystick, while overcoming visibility and size limitations, offering improved user experience and versatility.

Implementation Method 1

an optical sensor configured to detect movement of the stylus over a surface

Methodology Applied
Scientific EffectOptical sensing: Reflection

Implementation Method 2

a pointing stick extending from an opposite end of the stylus

Methodology Applied
Scientific EffectMechanical force sensing: Force

Implementation Method 3

The signal emitted by the active stylus is picked up by the digitizer sensor when electrostatic coupling is established between the writing tip and a portion of the matrix of electrode junctions

Methodology Applied
Scientific EffectElectrostatic coupling: Electrostatics

Data Source

PatentEP4020140B1Multi-functional stylus
Publication Date: 2025.06.25 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4020140B1 patent drawingFigure 1
  • EP4020140B1 patent drawingFigure 2A
  • EP4020140B1 patent drawingFigure 2B

AI summary

A stylus includes an elongated housing, a tip extending from a first end of the elongated housing and a tri-axial force sensor mounted on a second end. A first wireless transmitter transmits a signal via the tip based on which the tip interacts with a digitizer sensor of a touch screen. The tri-axial force sensor senses contact force applied by a user pressing against the tri-axial sensor. A second wireless transmitter transmits output sensed by the tri-axial force sensor. The stylus further includes a controller that controls transmission of the first wireless transmitter and the second wireless transmitter.