Inductively Coupled Photodetector for Broad Spectrum Sensing

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Solution Overview

Problem

Conventional photodetectors, such as wavelength-limited photodiodes, often require filters or adjusted depletion regions to detect specific wavelengths, limiting their versatility and efficiency in capturing a wide range of light spectra.

Innovation Solution

An inductively-coupled photodetector utilizing a semiconductor structure with a direct band gap material for electron-hole generation, where variations in a magnetic field induced by eddy currents detect the presence or absence of light, allowing for higher response frequencies and flexible implementation based on light frequency, without relying on carrier collection within the photosensitive material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wavelength-limited photodiodes use filters or adjusted depletion regions to detect specific wavelengths, then measurement precision for specific wavelengths is improved, but adaptability to detect a wide range of light spectra deteriorates

Engineering Contradiction:

Improvedetection precision for specific wavelengthsVSAvoidversatility in capturing light spectra

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The photodetector device is designed to detect multiple wavelengths of light (ultraviolet, visible, and infrared spectra) using a single integrated structure. The device employs a first photodetector for ultraviolet detection, a second photodetector for visible light detection, and a third photodetector for infrared detection, all within one device, eliminating the need for separate filters or wavelength-specific devices while maintaining detection precision across the spectrum.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If conventional photodetectors use carrier collection within photosensitive material to detect light, then detection mechanism is simple, but response frequency and efficiency deteriorate

Engineering Contradiction:

Improvesimplicity of detection mechanismVSAvoidresponse frequency and detection efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The invention replaces the conventional carrier collection mechanism with a magnetic field-based detection mechanism. Instead of relying on charge carrier generation and collection within the photosensitive material, the device uses changes in magnetic field strength (detected through inductance changes) to sense light presence. This substitution significantly improves response frequency and detection efficiency while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If photodetectors are designed for specific wavelength ranges, then manufacturing precision for that range is improved, but ease of operation across different wavelengths deteriorates

Engineering Contradiction:

Improveprecision for specific wavelength detectionVSAvoidoperational flexibility across wavelengths

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The photodetector device is segmented into three distinct photodetector units, each optimized for a specific wavelength range (ultraviolet, visible, and infrared). Each segment can be independently designed and manufactured with high precision for its target wavelength range, while the overall integrated device provides ease of operation across the entire spectrum by simply activating the appropriate segment based on the detection requirements.

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 approach enables efficient detection of light across various wavelengths with higher response frequencies and efficiency, as the change in magnetic field strength due to light presence or absence is directly correlated with inductance changes, facilitating more flexible and effective light sensing.

Implementation Method 1

When exposed to electromagnetic radiation, such as infrared (IR), visible, and ultraviolet (UV) light, a photodiode generates a number of electron-hole pairs at different depths within the device depending upon the depth at which the electromagnetic radiation was absorbed by the device

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

An inductively-coupled photodetector utilizes a semiconductor structure with a direct band gap material for electron-hole generation, where variations in a magnetic field induced by eddy currents detect the presence or absence of light

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

variations in a magnetic field induced by eddy currents detect the presence or absence of light

Methodology Applied

Scientific EffectEddy Currents: Eddy Currents

Data Source

PatentUS8390025B2Inductively coupled photodetector and method of forming an inductively coupled photodetector

Publication Date: 2013.03.05 NAT SEMICON CORP

AI summary

A photodetector detects the absence or presence of light by detecting a change in the inductance of a coil. The magnetic field generated when a current flows through the coil passes through an electron-hole generation region. Charged particles in the electron-hole generation region come under the influence of the magnetic field, and generate eddy currents whose magnitudes depend on whether light is absent or present. The eddy currents generate a magnetic field that opposes the magnetic field generated by current flowing through the coil.