Optoelectronic String Pickup with Spurious Light Filtering

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Solution Overview

Problem

Current string instrument pickups, particularly magnetic and optical pickups, face limitations in accurately representing string vibrations, are susceptible to interference, and require installation in new instruments, imposing economic burdens on musicians who wish to enhance sound quality.

Innovation Solution

An optoelectronic pickup system using light sources and photoreceivers with filtering mechanisms to control spurious light, allowing precise detection of string position and vibration, and enabling installation on existing instruments, thereby enhancing sound generation and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic pickups are used to produce sound, then sound generation is achieved, but accuracy in representing string vibrations is limited and susceptibility to magnetic interference increases

Engineering Contradiction:

Improvesound qualityVSAvoidmagnetic interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the magnetic field-based detection system with an optical detection system. Instead of using magnets and wire coils to detect string vibrations, the invention uses light sources and photodetectors to optically sense the position and movement of strings, thereby eliminating susceptibility to magnetic interference while maintaining sound generation capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary medium between the string and the detection system. By using light sources to illuminate the strings and photodetectors to detect the reflected or transmitted light, the system creates an optical pathway that is immune to magnetic interference while still accurately representing string vibrations

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If optical pickups are installed in new instruments, then precise string position detection is achieved, but economic burden increases due to requiring new instrument purchase

Engineering Contradiction:

Improvestring position detectionVSAvoidinstrument installation

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent divides the optical pickup system into separate, modular components that can be independently installed. The light sources, photodetectors, and associated electronics are configured as discrete units that can be attached to existing instruments without requiring complete instrument replacement or complex factory integration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent designs the optical pickup system to be universally applicable to existing string instruments. The modular configuration allows the same detection system to be installed on various instrument types without custom manufacturing, enabling musicians to enhance their current instruments rather than purchasing new ones

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If trans-illumination optical configuration is used, then string position detection is enabled, but susceptibility to ambient light interference and limited sensing range occur

Engineering Contradiction:

Improvestring position detectionVSAvoidambient light interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs modulated light sources that dynamically vary in intensity or frequency, allowing the detection system to distinguish between the modulated light signal and static ambient light. This dynamic approach enables the photodetectors to selectively respond to the intended light source while filtering out constant background illumination

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses periodically modulated light sources, such as LEDS driven at specific frequencies, to create a time-varying optical signal. The detection system is synchronized to this periodic modulation, allowing it to extract the string position information from the modulated light while rejecting non-modulated ambient light through frequency-selective detection

Inventive Principle:

Principle #19Periodic action

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 optoelectronic pickup system provides enhanced sound quality by capturing more frequency content, reducing interference, and allowing musicians to modify sound characteristics, while being adaptable to existing instruments, offering greater control and expressiveness.

Implementation Method 1

at least one photoreceiver located to detect reflected light from the string

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

at least one photoreceiver located to detect reflected light from the string so as to generate an electrical signal

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS9734811B2Instrument pickup

Publication Date: 2017.08.15 LIGHT4SOUND

AI summary

A optoelectronic pickup for a musical instrument includes at least one light source which directs light to impinge a string of the musical instrument in at least one photoreceiver located to detect the reflected light, so as to generate an electrical signal that is responsive to string vibrations. A number of dissimilar filter approaches are included to control undesired effects of spurious light, the filter approaches may be structure-based, signal processing-based, and/or optics-based.