Vehicle Indication Unit Using Pulse-Width Modulation for LED Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle indication units, particularly exterior mirror indicators, face challenges in meeting legal light intensity requirements while minimizing LED usage and preventing overheating, and they struggle to effectively utilize human perception of pulse length for enhanced visibility.
Innovation Solution
An indication unit that operates LEDs with short current pulses and pulse-width modulation signals at frequencies over 100 Hz, using a second control circuit to overlay signals, which reduces average energy consumption and leverages the Broca-Sulzer effect for enhanced visibility while maintaining legal light intensity standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LEDs are operated continuously to meet legal light intensity requirements, then visibility is ensured, but LED lifespan is reduced and overheating occurs
Solution Approach 1:
The patent applies periodic action by operating LEDs with short current pulses instead of continuous operation. The control circuit generates pulse signals with frequencies over 100 Hz, creating periodic illumination that exploits the Broca-Sulzer effect to enhance perceived brightness while reducing thermal accumulation and extending LED operational life.
2Illumination intensity
If more LEDs are used to increase light intensity, then visibility is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the operational parameters of the LEDs by implementing pulse-width modulation with frequencies over 100 Hz. This parameter change allows fewer LEDs to achieve the same perceived brightness due to the Broca-Sulzer effect, thereby reducing construction complexity and cost while maintaining visibility requirements.
3Illumination intensity
If pulse frequency is increased to exploit Broca-Sulzer effect, then perceived brightness is enhanced, but energy consumption increases
Solution Approach 1:
The patent uses periodic action with carefully controlled pulse frequencies over 100 Hz and specific duty cycles. This periodic operation exploits the Broca-Sulzer effect to enhance perceived brightness while the duty cycle control ensures that the average power consumption remains within acceptable limits, balancing visual effectiveness with energy efficiency.
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 extends LED lifespan, reduces overheating, and optimizes light intensity perception by the human eye, ensuring compliance with legal requirements while minimizing LED usage and thermal issues.
Implementation Method 1
The present invention uses a pulse-width modulation for LEDs, in order to raise the lifespan of the LEDs, on one hand, and on the other hand, in order to exploit an optical effect, which is known as the Broca-Sulzer effect. This effect describes the physiological behavior of the human eye, which perceives short pulses of a certain length as brighter than pulses of a longer length.
Data Source
AI summary
An indication unit for vehicles is suggested, which comprises at least one LED and at least one electrical circuit in a housing. The indication unit is connected to a first control, which is arranged in the vehicle, and connected to an LED driver circuit. A second control circuit, which is arranged in or on the housing of the indication unit, operates the LED with pulse-width modulated signals.