LED Unit with Measuring Unit for Failure Detection

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Solution Overview

Problem

Conventional LED light signal transmitters for level crossings face issues with operational reliability, cost, maintenance effort, and service life, particularly due to the difficulty in monitoring failures in high-power LED systems, where internal short circuits can go undetected, leading to continued current flow and failure to report errors.

Innovation Solution

An LED unit with a lighting system comprising two LED strings connected to separate power sources, a controller for alternating their operation, and a measuring unit to detect failures, including a third switching device for switchover in case of return conductor damage, and voltage monitoring to identify individual LED failures, ensuring continued operation and error messaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high-power LEDs are used to reduce the number of LEDs needed, then illumination intensity is improved, but reliability deteriorates because internal short circuits cannot be detected by conventional current monitoring

Engineering Contradiction:
Improveillumination intensityVSAvoidreliability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent introduces a measuring unit as an intermediary component that monitors the electrical characteristics of individual LEDs. This measuring unit detects changes in forward voltage or current flow through each LED, enabling the system to identify failed LEDs even when they experience internal short circuits. The measuring unit acts as a mediator between the power source and LEDs, providing failure detection capability that conventional direct current monitoring lacks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback through the measuring unit that continuously monitors LED performance and provides information about their operational status. When an LED failure is detected, the feedback mechanism triggers a switchover to a standby LED, ensuring continuous operation. This feedback loop enables real-time monitoring and automatic response to failures, maintaining system reliability despite using high-power LEDs.

Inventive Principle:
Principle #23Feedback

2Device complexity

If conventional current monitoring is used to detect LED failures, then device complexity is reduced, but measurement precision deteriorates because internal short circuits are not detected

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The measuring unit serves as an intermediary between the power source and LEDs, providing enhanced measurement capabilities. It measures electrical characteristics such as forward voltage or current through each individual LED, enabling detection of internal short circuits that conventional monitoring would miss. This intermediary component adds measurement precision without requiring complete system redesign.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system monitors changes in electrical parameters (forward voltage, current) of individual LEDs to detect failures. By measuring these parameters and comparing them against expected values, the system can identify when an LED has failed due to an internal short circuit. This parameter-based monitoring approach provides precise failure detection while maintaining relatively simple device architecture.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If LEDs without individual monitoring are used, then manufacturing precision requirements are reduced, but reliability deteriorates due to undetected failures and continued operation with faulty components

Engineering Contradiction:
Improvemanufacturing precisionVSAvoidreliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The measuring unit provides feedback about the operational status of each LED, enabling the system to respond to failures automatically. When an LED failure is detected, the feedback triggers a switchover to a standby LED, ensuring continuous reliable operation. This feedback mechanism compensates for potential manufacturing variations by monitoring actual performance rather than relying solely on manufacturing specifications.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The measuring unit acts as an intermediary that bridges the gap between manufacturing variations and system reliability. It monitors each LED's electrical characteristics and identifies failures regardless of manufacturing precision variations. This intermediary monitoring system ensures that even LEDs with moderate manufacturing precision can operate reliably through automatic failure detection and switchover mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances operational reliability by detecting and addressing failures in LED units, reducing maintenance efforts, and extending service life while providing cost-effective error messaging and continued functionality even if the return conductor is damaged.

Implementation Method 1

LED unit for light signal transmitters

Methodology Applied
Scientific EffectLight-emitting diode (LED): Light Emitting Diode

Implementation Method 2

lighting unit comprising a first LED string and a second LED string

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2979955B1LED unit for light signal transmitter and light signal emitter with such a unit
Publication Date: 2016.11.09 PINTSCH BAMAG AG
  • EP2979955B1 patent drawingFigure 1A~2C
  • EP2979955B1 patent drawingFigure 3
  • EP2979955B1 patent drawingFigure 4

AI summary

LED unit for light signal devices, comprising a light unit with a three-pole connector, a first light source (11) with a first LED string, a second light source (12) with any connection direction and a second LED string, a first switching device (21) on a first pole (31) of the three-pole connector, with which the first LED string is connected in series between the first pole (31) and a third pole (33) of the three-pole connector, a second switching device (22) on a second pole (32) of the three-pole connector, with which the second LED string is connected in series between the second pole (32) and the third pole (33), a return conductor between the third pole and a power source connection pole (4), a control of the first and second switching devices (21, 22), which includes a first control function for alternately switching on the first and second LED strings with the first and second switching devices (21, 22),and a measuring unit (51, 52, 61, 62, 71, 72, 81, 82) of the control unit with a function for detecting a failure of the lighting unit, further comprising: a third switching device (23) at the power source connection pole (4), wherein the second light source (12) is connected between the third pole and the third switching device (23), a second control function of the control unit for non-alternating connection of the first light source (11) with the first switching device (21) to the first pole and connection of the second light source (12) to the power source connection pole (4) with the third switching device (23) when disconnected with the second switching device (22) from the second pole (32), and a switching function of the control unit for switching from the first to the second control function when the failure is detected by the measuring unit.