Parallel LED Light Source with High Internal Resistance

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Solution Overview

Problem

LED assemblies in motor vehicles experience inefficient energy use due to non-uniform current distribution among branches, leading to varying luminous intensity and reduced lifespan, especially in matrices with many parallel branches, where multiple current sources are necessary, reducing overall efficiency.

Innovation Solution

A light source with a parallel assembly of branches, each containing electroluminescent semiconductor elements with identical high internal series resistance (1-100 ohms), eliminating the need for external current regulation devices, and utilizing a voltage source with a microcontroller to manage switches and compensate for temperature-dependent voltage drops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple current sources are used to regulate current in each branch of parallel LED assemblies, then uniform current distribution and luminous intensity are improved, but device complexity and energy efficiency deteriorate

Engineering Contradiction:
Improveuniform current distributionVSAvoidnumber of current sources
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the resistance parameter of the LED components by selecting and grouping LEDs with specific resistance values. By ensuring that all LEDs in parallel branches have substantially equal resistance values, the system achieves uniform current distribution without requiring complex current regulation circuits in each branch.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates equipotential conditions across parallel branches by equalizing the resistance parameters of LEDs in each branch. This ensures that voltage and current are distributed uniformly across all branches when connected to a common voltage source, eliminating the need for individual current regulation.

Inventive Principle:
Principle #12Equipotentiality

2Reliability

If multiple current sources are used to regulate current in each branch of parallel LED assemblies, then uniform luminous intensity is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improveuniform luminous intensityVSAvoidenergy efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention changes the resistance parameter of the LED components by selecting and grouping LEDs with specific resistance values. By ensuring that all LEDs in parallel branches have substantially equal resistance values, the system achieves uniform current distribution without requiring complex current regulation circuits in each branch.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts and removes the current regulation function from individual branch circuits. Instead of using active current regulation devices in each branch, the system achieves current uniformity passively through resistance matching, thereby eliminating unnecessary energy consumption by regulation devices.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If LEDs with different characteristics are grouped together in parallel branches, then manufacturing ease is improved, but current distribution uniformity and lifespan deteriorate

Engineering Contradiction:
Improvegrouping flexibilityVSAvoidLED lifespan
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The invention changes the resistance parameter of the LED components by selecting and grouping LEDs with specific resistance values. By ensuring that all LEDs in parallel branches have substantially equal resistance values, the system achieves uniform current distribution without requiring complex current regulation circuits in each branch.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality control by ensuring that each parallel branch has uniformly matched LED characteristics. This localized matching ensures that current is distributed evenly across all branches, preventing overheating and extending the lifespan of the LED assembly.

Inventive Principle:
Principle #3Local quality

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 configuration ensures uniform current distribution and brightness across branches, enhancing energy efficiency by eliminating the need for current regulation devices, resulting in a higher ratio of optical power to electrical power input.

Implementation Method 1

A light-emitting diode, LED, is an electronic component capable of emitting light when it is flowed through by an electric current

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

Each LED is additionally characterized by an internal series resistance, due to the presence of a plurality of non-light-emitting semiconductor layers, which serve only to transport electrons or to transport electron holes

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

The value of the forward voltage depends mainly on the wavelength of the emitted light, which defines the energy of the emitted photon in eV

Methodology Applied
Scientific EffectPhoton emission:

Data Source

PatentEP3531453B1Electroluminescent light source intended to be supplied with power by a voltage source
Publication Date: 2023.06.07 VALEO VISION SA
  • EP3531453B1 patent drawingFigure 1~3
  • EP3531453B1 patent drawingFigure 4

AI summary

The invention relates to a light source intended to be supplied with power by a voltage source. The light source comprises a parallel assembly of at least two branches, each branch comprising at least one elementary light source having an electroluminescent semiconductor element, and each of the elementary light sources has a high internal series resistance. The invention also relates to a method for manufacturing a light source according to the invention.