OLED Motor Vehicle Light Series-Parallel Switching Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting diodes (OLEDs) face challenges in maintaining optimal voltage and current profiles across varying temperatures, especially below 0°C, due to their different electrical actuation requirements compared to LEDs, which complicates their use in motor vehicle lighting where temperature ranges from -40°C to 80°C and limited vehicle electrical system voltages are constraints.
Innovation Solution
A circuit arrangement with temperature sensors and adjustable electrical connections that switch between series and parallel configurations based on detected temperatures, ensuring OLEDs receive the necessary voltage to maintain a constant current, thereby compensating for the voltage requirements across the temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If OLEDs are used as light sources in motor vehicle lights, then lighting performance and design flexibility are improved, but voltage requirements become problematic at low temperatures below 0°C
Solution Approach 1:
The patent applies dynamic switching between series and parallel electrical connections based on temperature conditions. The circuit arrangement includes switching means that automatically reconfigure the electrical connections of OLEDs from series to parallel when temperature drops below a threshold, and vice versa when temperature rises. This dynamic adaptation allows the system to maintain proper voltage levels across varying temperatures without complex voltage conversion circuitry.
Solution Approach 2:
The patent changes the electrical connection configuration parameter (series/parallel arrangement) in response to temperature parameter changes. By monitoring temperature and switching between different connection topologies, the system adjusts the effective voltage delivered to OLEDs to match their temperature-dependent requirements, enabling reliable operation from -40°C to 80°C.
2Reliability
If electrical connections are reconfigured to compensate for low-temperature voltage requirements, then OLED operation is maintained, but device complexity increases due to switching means and temperature sensors
Solution Approach 1:
The circuit arrangement is designed to be self-regulating through automatic temperature monitoring and switching. The temperature sensor continuously monitors conditions and triggers appropriate switching actions without external intervention. This self-service approach maintains OLED reliability while minimizing the need for complex external control systems or manual adjustments.
Solution Approach 2:
The system incorporates temperature sensing and feedback control mechanisms. The temperature sensor provides real-time information about thermal conditions to the switching means, which then adjusts the electrical connection configuration accordingly. This closed-loop feedback ensures that OLEDs receive appropriate voltage levels across the full temperature range while using simple, straightforward control logic.
3Reliability
If complex voltage conversion circuits are used to maintain constant voltage, then OLED performance is stable, but electromagnetic compatibility is degraded due to additional shielding requirements
Solution Approach 1:
The patent replaces complex voltage conversion circuits (electrical/electronic system) with a mechanical switching approach that reconfigures existing electrical connections between series and parallel arrangements. This substitution eliminates the need for complex DC-DC converters and associated electromagnetic interference shielding, while still achieving stable OLED operation across temperature variations. The solution uses simple switches and temperature sensors instead of complex power conversion electronics.
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
Enables the reliable operation of OLEDs in motor vehicle lights over a wide temperature range, ensuring consistent lighting performance and adherence to thermal stability requirements, without the need for complex voltage conversion or additional shielding, thus improving electromagnetic compatibility.
Implementation Method 1
with at least one temperature sensor (210) in at least one thermally conductive contact with at least one OLED (20)
Implementation Method 2
An OLED is a thin-film luminous device made of organic semiconducting materials with at least one emitter layer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light source (100) comprising at least two OLEDs (20) as light sources, a motor vehicle lamp (01) equipped with at least one such light source (100), and a method for operating at least one such light source (100) and/or a motor vehicle lamp (01) equipped with at least one such light source (100) are described. It is provided that, below at least a predetermined threshold temperature, at least two OLEDs are connected in parallel during operation of the light source (100) until the OLEDs (20) connected in parallel during operation of the light source (100) have heated at least themselves and/or an environment surrounding them to a temperature above a predetermined threshold temperature, and at least two OLEDs (20) are connected in series at any given time from and/or above a predetermined threshold temperature.