Semiconductor Light Source With Distinct Emission Regions

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Solution Overview

Problem

Existing methods for controlling electric current in semiconductor light sources struggle to achieve high luminous flux dynamics, particularly when switching between different functions like 'daytime running light' and 'position light,' due to limitations in pulse width modulation, leading to inefficiencies and electromagnetic compatibility issues, and are costly to resolve.

Innovation Solution

The method involves a semiconductor light source with selectively activatable light emission zones, allowing independent adjustment of luminous flux for each zone using a conventional adjustment member, enabling a broader range of luminous flux adjustment without sacrificing precision or causing electromagnetic disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pulse-width modulation (PWM) control with minimum duty cycle of 5-7% is used to control electric current in semiconductor light source, then current control accuracy is maintained, but luminous flux dynamics are limited and cannot achieve ratio greater than or equal to 20

Engineering Contradiction:

Improveluminous flux dynamicsVSAvoidcurrent control accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The semiconductor light source is divided into multiple independently controllable light emission regions (first region and second region). Each region can be controlled separately through PWM, allowing the system to achieve higher overall flux dynamics by combining different region states (both on, one on, both off) rather than relying solely on duty cycle variation of a single region.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If duty cycle is reduced below 5% to achieve higher luminous flux dynamics, then flux ratio can be increased, but soft edges appear in current control and efficiency losses occur

Engineering Contradiction:

Improveluminous flux dynamicsVSAvoidefficiency loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

By segmenting the light source into multiple regions, the system can achieve dimmer overall output by activating fewer regions rather than using extremely low duty cycles on a single region. This avoids the soft edge and efficiency loss problems associated with duty cycles below 5%.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If a resistor is added to the control system to dissipate energy from soft edges, then electromagnetic compatibility problems are reduced, but system cost increases significantly

Engineering Contradiction:

Improveelectromagnetic compatibilityVSAvoidsystem cost

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent avoids adding external components like resistors by using the existing multi-region structure of the light source. By controlling which regions are active, the system naturally reduces the severity of soft edges and electromagnetic interference without requiring additional energy-dissipating components, thus avoiding increased system cost.

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If multiple light emission regions are used to increase luminous flux dynamics, then flux ratio can reach 100:1, but device complexity increases

Engineering Contradiction:

Improveluminous flux dynamicsVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple light emission regions within a single semiconductor device structure. The control system manages multiple regions through integrated control signals, achieving high flux dynamics (100:1 ratio) while keeping the overall device structure unified and the control logic consolidated, rather than requiring separate external control systems for each region.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances luminous flux dynamics by allowing a ratio of extreme flux values greater than or equal to 100, achieved at reduced cost and without efficiency loss or electromagnetic interference, maintaining uniform visual rendering across varying flux values.

Implementation Method 1

semiconductor light source defining at least two distinct light emission regions on its substrate

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3616471B1Method and system for controlling the electric current within a semiconductor light source defining at least two distinct light emission regions

Publication Date: 2024.01.31 VALEO VISION SA

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AI summary

The present invention relates to a method for controlling an electric current within a semiconductor light source, said light source comprising a substrate where at least two light-emitting regions are distinct, the method comprising the following steps: - activating a first luminous region, - regulating the mean value of the electrical quantity relating to the electric current received by the light source according to a first setpoint so as to obtain a first value of a first light flux corresponding to the flux emitted by said first luminous region, - activating at least a second luminous region of the light source, - regulating the mean value of the electrical quantity relative to the electrical current received by the light source so as to obtain a second value of a second light flux corresponding to the flux emitted by at least said second luminous region.