Compensating Failed Pixels in Pixelated Vehicle Headlamps
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Solution Overview
Problem
Advanced vehicle headlamp systems with pixelated LED matrices face challenges in manufacturing and operational reliability due to inoperable LEDs, which can lead to reduced production yield and compromised lighting performance.
Innovation Solution
The implementation of vehicle headlamp control circuits that include a memory to store information for compensating failed LEDs, using neighboring LEDs to adjust duty cycles or gamma corrections, and utilizing a graphics processing unit (GPU) to send compensating values to an LED driver to enhance lighting output and make failures imperceptible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LED matrices are manufactured with high density and complexity to enable advanced lighting effects, then lighting performance and versatility are improved, but manufacturing precision and reliability deteriorate due to higher likelihood of failed LEDs
Solution Approach 1:
The patent applies local quality by assigning different driving parameters to different regions of the LED matrix. Specifically, LEDs adjacent to failed LEDs are assigned compensatory driving parameters (higher duty cycles or gamma corrections) while non-adjacent LEDs use standard parameters. This localized adjustment maintains overall lighting uniformity without requiring uniform changes across the entire matrix, thereby preserving reliability while maintaining versatility.
Solution Approach 2:
The patent changes operational parameters (duty cycle and gamma correction values) of specific LEDs based on their proximity to failed LEDs. By dynamically adjusting these parameters, the system compensates for failed LEDs and maintains consistent lighting output. This parameter change approach allows the system to adapt to manufacturing variations and failures without sacrificing the advanced lighting effects enabled by high-density matrices.
2Reliability
If strict quality control is applied during LED matrix manufacturing to ensure zero failed LEDs, then reliability is improved, but production yield and cost efficiency deteriorate
Solution Approach 1:
The patent applies preliminary action by identifying and compensating for failed LEDs during the manufacturing or initialization phase. The system creates a compensation map that records the locations of failed LEDs and pre-calculates the necessary driving parameter adjustments for adjacent LEDs. This preliminary compensation enables the LED matrix to be used even with some failed LEDs, thereby improving production yield without compromising operational reliability.
Solution Approach 2:
The patent converts the harmful effect of failed LEDs into a beneficial outcome by using the compensation mechanism. Instead of discarding entire LED matrices due to failed LEDs (which would reduce productivity), the system leverages the failed LED locations as information to adjust adjacent LED parameters, ultimately achieving uniform lighting output. This approach transforms manufacturing defects into opportunities for optimized local control.
3Illumination intensity
If failed LEDs are compensated by increasing the driving parameters of neighboring LEDs, then lighting uniformity is improved, but energy consumption and heat generation worsen
Solution Approach 1:
The patent applies local quality by restricting increased driving parameters only to LEDs adjacent to failed LEDs, rather than uniformly increasing parameters across the entire matrix. This localized approach achieves the necessary lighting uniformity in affected regions while minimizing overall energy consumption. Non-adjacent LEDs continue to operate at standard parameters, thereby reducing total energy usage and heat generation compared to a global parameter increase.
Data Source
AI summary
A vehicle headlamp control circuit is configured to control a vehicle headlamp comprising a plurality of lighting elements. The vehicle headlamp control circuit may comprise a memory that stores information for controlling the plurality of lighting elements, and a driver circuit that drives the plurality of lighting elements based on the information, wherein the information compensates for one or more failed elements of the plurality of lighting elements.