LED Signal Light Tilted Optical Axis Reduces Phantom Light

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Solution Overview

Problem

Existing LED signal lights in rail traffic face issues with phantom light, which affects their visibility and safety, particularly under strict test requirements, and previous solutions compromise compactness and effectiveness.

Innovation Solution

The optical axis of light-receiving and bundling components is tilted to homogenize and collimate light, reducing phantom light effects by ±3 to 8 degrees, while allowing for redundant and separately controllable LEDs of different colors, enabling a compact, versatile, and fail-safe universal LED signal light design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If external shields and internal baffles are installed to reduce phantom light effects, then phantom light reduction is improved, but device complexity increases

Engineering Contradiction:
Improvephantom light effectsVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and removes the circuit board from the light housing entirely, eliminating the source of phantom light reflections. This approach avoids the need for additional shields and baffles, thereby reducing device complexity while still effectively reducing phantom light effects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent positions the LEDs and optical components such that the circuit board is located in an area not exposed to incoming light before the light reaches the optical path. This preliminary positioning prevents phantom light from occurring in the first place, eliminating the need for corrective shielding measures.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If circuit boards are positioned deep within the light housing to reduce phantom light, then phantom light reduction is improved, but device compactness deteriorates

Engineering Contradiction:
Improvephantom light effectsVSAvoidhousing volume
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The circuit board is extracted from the light housing and positioned separately in an area not exposed to incoming light. This eliminates the need to deepen the housing to accommodate the circuit board, maintaining compactness while preventing phantom light reflections.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of positioning the circuit board deeper within the housing (z-dimension), the patent relocates it to a different spatial arrangement where it is not in the light path. This dimensional repositioning maintains housing compactness while achieving phantom light reduction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If known phantom light reduction measures are applied, then phantom light effects are reduced, but effectiveness under stringent test requirements deteriorates

Engineering Contradiction:
Improvephantom light effectsVSAvoidtest requirement compliance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

By completely removing the circuit board from the light housing, the patent eliminates the primary source of phantom light reflections. This radical extraction approach provides superior phantom light reduction compared to incremental measures like shields and baffles, ensuring compliance with stringent test requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs preliminary design arrangements where LEDs and optical components are positioned to prevent incoming light from reaching the circuit board. This proactive prevention ensures reliable phantom light reduction under all test conditions, including oblique lighting angles.

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

This approach significantly reduces phantom light effects, enhances compactness, and allows for various application scenarios, meeting stringent user requirements while ensuring high reliability and flexibility in signal light generation.

Implementation Method 1

a first optical component (16) having sections (18) for receiving and focusing the light emitted by each LED (14)

Methodology Applied
Scientific EffectLight refraction and focusing: Refraction

Implementation Method 2

a cuboid section integrally formed on the sections (18) for receiving and focusing, for homogenizing the light

Methodology Applied
Scientific EffectLight homogenization:

Implementation Method 3

a second optical element (22) which has a section for collimating the homogenized light emerging from the first optical element

Methodology Applied
Scientific EffectLight collimation:

Implementation Method 4

a retaining disk (20) having a dual function with regard to holding the first optical element (16) and preventing phantom light reflections

Methodology Applied
Scientific EffectLight reflection prevention: Reflection

Data Source

PatentEP3296182B1LED signal light
Publication Date: 2019.02.27 PINTSCH TIEFENBACH
  • EP3296182B1 patent drawingFigure 1~2
  • EP3296182B1 patent drawingFigure 3~4
  • EP3296182B1 patent drawingFigure 5~6

AI summary

LED signal lamp (10) particularly for rail transport with a number of LEDs (14) and a number of optical components (16, 22) with sections for receiving and focusing the light emitted by the LEDs during operation, homogenizing the received and focused light, collimating the homogenized light and scattering the homogenized light to achieve a luminous intensity distribution specified with respect to a predefined main emission direction (32), wherein the optical axis (30) of the sections for receiving and focusing, homogenizing and collimating the light emitted by the LEDs in the intended mounting state of the signal lamp (10) deviates by an angle of about ± 3 to 8 degrees, preferably about 5 to 6 degrees vertically from the main emission direction (32).