Light Sensor With Ion-Doped Intrinsic Layer for Touch Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional light sensors used in touch-control LCDs have reduced light transmittance and increased thickness due to the use of resistor or capacitor types, while optical touch panels are bulky, and traditional poly-Si intrinsic layers have lower sensitivity in sensing visible light.

Innovation Solution

A light sensor with an intrinsic layer comprising a first and second ion doping area, an oxide insulating layer, and a gate metal, formed using a simplified process involving poly crystalline silicon thin film ion-implantation and deposition, which enhances light sensitivity without the need for complex CMOS processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional resistor or capacitor types are used in touch-control LCDs, then touch control function is achieved, but light transmittance is decreased and thickness is increased

Engineering Contradiction:

Improvetouch control functionVSAvoidlight transmittance

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent replaces conventional resistor or capacitor type touch control mechanisms with an optical detection system using light sensors and light sources. This substitution eliminates the need for physical resistors or capacitors on the panel, thereby maintaining touch control functionality while preserving light transmittance and reducing panel thickness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light sources and light sensors as intermediary elements to detect touch positions optically. Instead of using electrical resistors or capacitors directly on the panel, the system uses light as a mediator to detect touch coordinates, achieving accurate touch control without compromising optical properties of the display.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If optical detecting elements are disposed around the LCD panel, then touch detection is achieved, but product size is significantly increased

Engineering Contradiction:

Improvetouch detection functionVSAvoidproduct size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent integrates light sources and light sensors directly within the LCD panel structure, nesting them between the upper and lower substrates. This nesting approach allows the optical detection system to be embedded within the existing panel volume, eliminating the need for external components and reducing overall product size.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a planar arrangement where detecting elements are disposed around the panel to a three-dimensional integration where light sources and sensors are positioned between the upper and lower substrates. This dimensional change allows compact integration within the panel thickness, reducing the horizontal space requirements and overall product footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If poly-Si process is used to manufacture the intrinsic layer, then manufacturing is achieved, but light sensitivity in sensing visible light is reduced

Engineering Contradiction:

Improveintrinsic layer fabricationVSAvoidlight sensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the material composition parameter of the intrinsic layer from poly-Si to a-Si (amorphous silicon). This parameter change significantly improves light sensitivity in the visible range while maintaining compatibility with standard semiconductor manufacturing processes, thereby resolving the contradiction between ease of manufacture and light sensitivity.

Inventive Principle:

Principle #35Parameter changes

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

The solution achieves improved light sensitivity and reduced manufacturing complexity, resulting in a more compact and efficient light sensor with increased photocurrent generation in response to varying luminance levels.

Implementation Method 1

The first light sensing region adjacent to the first ion doping area is used for generating electron-hole pairs in response to luminance of incident light

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

ion-implanting the poly crystalline silicon thin film by using a first mask to form a first ion doping area and a second ion doping area

Methodology Applied

Scientific EffectIon Implantation: Ion Implantation

Data Source

PatentUS8044473B2Light sensor

Publication Date: 2011.10.25 AU OPTRONICS CORP

AI summary

A light sensor includes an intrinsic layer, a first ion doping area disposed one side of the intrinsic layer, a second ion doping area disposed at the other side of the intrinsic layer, an oxide insulating layer on the intrinsic layer, and a gate metal on the oxide insulating layer. The first and second ion doping areas have the same P type or N type doped ions. The intrinsic layer further includes a first light sensing region close to the first ion doping area. The first light sensing region is used for generating electron-hole pairs based on luminance of incident light.