Photo Sensor Input Apparatus for Simultaneous Finger and Light Pen Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional photo-sensor type touch apparatuses face difficulties in simultaneously detecting touch events triggered by fingers and light pens due to unstable ambient light conditions, which affect the voltage settings required for accurate signal identification.

Innovation Solution

The implementation of dedicated first and second photo sensing devices with distinct light sensing abilities, where the first device is designed for illumination touch events triggered by light pens and the second for shadow touch events triggered by fingers, using different transmittance, filter sets, and circuit designs to enhance light sensing capabilities and achieve proper bias ranges for reliable detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single photo sensor is used to detect both finger touch and light pen input, then the device complexity is reduced, but the measurement precision deteriorates because ambient light instability makes it difficult to distinguish between different input types

Engineering Contradiction:

Improvephoto sensor configurationVSAvoidinput event detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the photo sensing function into two separate photo sensors: a first photo sensor for detecting light pen inputs (which emit light) and a second photo sensor for detecting finger touch inputs (which block light). This segmentation allows each sensor to be optimized for its specific detection task, resolving the measurement precision issue while maintaining reasonable device complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by giving different photo sensors different characteristics - the first photo sensor is configured with specific spectral sensitivity to detect light pen emissions, while the second photo sensor is configured to detect the absence of light (shadow) caused by finger touches. Each sensor has localized optimization for its specific function

Inventive Principle:

Principle #3Local quality

2Reliability

If the gate-to-source voltage is adjusted to optimize detection of light pen inputs, then the detection reliability for light pen events improves, but the ability to detect finger touch events deteriorates due to shifted voltage operating points

Engineering Contradiction:

Improvelight pen detection reliabilityVSAvoidfinger touch detection precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By separating the detection of light pen inputs and finger touch inputs into two different photo sensors, the patent eliminates the need to compromise voltage settings. Each sensor can operate at its optimal voltage point for its specific detection task, with the first sensor optimized for light detection and the second for shadow detection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters (gate-to-source voltage) independently for each photo sensor based on its specific function. The first photo sensor uses voltage settings optimized for detecting light pen emissions, while the second photo sensor uses different voltage settings optimized for detecting finger-induced light blocking, thereby resolving the parameter conflict

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If dedicated photo sensing devices with different light sensing abilities are implemented, then the measurement precision for distinguishing different input types improves, but the device complexity increases due to additional sensors and circuitry

Engineering Contradiction:

Improveinput event differentiation accuracyVSAvoidphoto sensing system structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the photo sensing function into two specialized sensors, each handling a specific input type. This segmentation improves measurement precision by allowing each sensor to be optimized for its specific detection task, while the overall complexity increase is managed through systematic integration into the existing display structure

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

This solution allows for simultaneous and reliable detection of both finger and light pen touch events, improving signal identification reliability and facilitating mass production by ensuring distinct light sensing abilities for each type of input event.

Implementation Method 1

a thin film transistor (TFT) photo sensor generates different photo currents in response to different light intensities

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS8836673B2Photo-sensor type input apparatus for identifying different types of input events simultaneously, and related display apparatus thereof

Publication Date: 2014.09.16 AU OPTRONICS CORP

AI summary

A photo-sensor type input apparatus includes an upper substrate, a bottom substrate, at least one first photo sensing device, and at least one second photo sensing device. The bottom substrate is correspondingly disposed below the upper substrate. The first photo sensing device is disposed on the bottom substrate and arranged to detect a received first type input event. The second photo sensing device is disposed on the bottom substrate and arranged to detect a received second type input event. A light sensing ability of the first photo sensing device is different from a light sensing ability of the second photo sensing device.