Optical Sensor LED Identification via RC Discharge Sensing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing optical sensors lack an efficient method for automatically identifying LED types without requiring additional electrical connections between circuit boards, which are sensitive to measurement signals and disturbance.

Innovation Solution

A capacitor is connected in parallel with a thermistor on the second circuit board, forming an RC unit, allowing LED identification through measuring the discharge curve of the capacitor, which is specific to each LED type, and processed by the data processing unit on the first circuit board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional electrical connections are added between circuit boards for LED identification, then LED type identification capability is improved, but measurement signal integrity deteriorates due to disturbance susceptibility

Engineering Contradiction:

ImproveLED type identification capabilityVSAvoidmeasurement signal integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a capacitor as an intermediary component that enables LED identification without requiring additional signal transmission lines. The capacitor stores electrical charge characteristics that differ based on LED type, allowing the main board to identify the LED type by measuring discharge characteristics through existing power supply lines, thus avoiding direct measurement signal interference

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the need for additional electrical measurement connections with an electrical property-based identification method. Instead of adding physical measurement lines, the system uses the inherent electrical discharge characteristics of capacitors charged through different LED types to identify LED variations, substituting physical connection expansion with electrical property analysis

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If additional electrical connections are added between circuit boards, then LED type identification capability is improved, but device complexity increases

Engineering Contradiction:

ImproveLED type identification capabilityVSAvoidcircuit board complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The capacitor serves multiple functions: it acts as a filtering component for power supply stabilization and simultaneously serves as an identification marker for LED type recognition. This multi-functionality eliminates the need for separate identification circuitry, maintaining circuit simplicity while enabling LED type detection

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The capacitor's inherent electrical characteristics (charge/discharge behavior) automatically provide identification information based on the connected LED type. The system leverages the natural electrical properties of components already present in the circuit rather than requiring active identification mechanisms, reducing overall system complexity

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If additional electrical connections are added between circuit boards, then LED type identification capability is improved, but manufacturing complexity increases

Engineering Contradiction:

ImproveLED type identification capabilityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The capacitor is pre-selected and mounted on the additional board during manufacturing with specific capacitance values corresponding to different LED types. This preliminary configuration of identification characteristics simplifies the manufacturing process by eliminating the need for post-assembly identification setup or complex programming, allowing automatic identification to work out-of-the-box

Inventive Principle:

Principle #10Preliminary 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

Enables automatic LED identification with minimal hardware changes, maintaining normal operation and avoiding metrological changes, without the need for additional lines or memory updates during manufacturing.

Implementation Method 1

a capacitor (8), which is connected in parallel with the thermistor (11), wherein the capacitor (8) is embodied specifically for the LED (1)

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

measuring the discharge curve of the capacitor (8)

Methodology Applied

Scientific EffectRC circuit discharge:

Data Source

PatentUS12578376B2Optical sensor and method of detecting an LED in such a sensor

Publication Date: 2026.03.17 ENDRESS HAUSER CONDUCTA GMBH CO KG

AI summary

The present disclosure relates to an optical sensor, comprising: a first circuit board having at least a data processing unit and an interface to a second circuit board, wherein the interface is connected with the data processing unit; and the second circuit board having an LED, a thermistor and a capacitor, which is connected in parallel with the thermistor, wherein the capacitor is embodied specifically for the LED, and an interface to the first circuit board, wherein LED, thermistor and capacitor are connected with the interface. The present disclosure relates also to a method for identifying an LED in an optical sensor.