Laser Light Source Grouping for Display Brightness Uniformity
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Solution Overview
Problem
In image display devices using multiple laser light sources, maintaining uniform optical power output is challenging due to manufacturing variations and performance drift, leading to noticeable brightness differences and reduced image quality when one laser underperforms.
Innovation Solution
Organizing laser light sources into groups, adjusting the optical output power of one group to match the underperforming laser, while interleaving the outputs of other groups to maintain perceptual uniformity and compensate for reduced brightness, thereby minimizing overall image brightness loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If all lasers are reduced in power to match the under-performing laser, then brightness uniformity is improved, but overall image brightness is severely reduced
Solution Approach 1:
The patent divides the laser array into multiple groups (e.g., Group 1 and Group 2) where each group contains lasers that illuminate different regions of the display. By segmenting the lasers, the system can adjust power levels independently for each group, allowing some lasers to operate at higher power while maintaining overall brightness uniformity through interleaved scanning patterns.
Solution Approach 2:
The patent applies different power levels to different groups of lasers based on their performance characteristics. High-power lasers operate at maximum output while under-performing lasers operate at reduced power, with each group's power level optimized for its specific lasers rather than uniformly reducing all lasers to the level of the weakest one.
2Area of stationary object
If multiple light sources are used to illuminate different regions, then display coverage is improved, but brightness non-uniformity increases due to manufacturing variations
Solution Approach 1:
The patent segments the display area into different regions illuminated by different laser groups. Each laser group is assigned to specific display regions, and the scanning system interleaves the illumination patterns so that adjacent regions are illuminated by different groups, distributing the impact of laser performance variations across the entire display.
Solution Approach 2:
The patent implements dynamic power adjustment and interleaved scanning where the system actively manages which laser group illuminates which region at any given time. This dynamic approach allows the system to compensate for laser performance variations by rotating which lasers illuminate which areas, preventing fixed brightness patterns from forming.
3Stability of the object's composition
If laser power is tightly controlled to within 1% variation, then brightness uniformity is improved, but system complexity and calibration difficulty increase
Solution Approach 1:
The patent changes the power parameter of different laser groups to different levels rather than maintaining uniform power across all lasers. By accepting and utilizing power variations as a design parameter rather than trying to eliminate them, the system achieves brightness uniformity through the interleaved scanning pattern and human visual averaging rather than through tight power control.
Data Source
AI summary
A technique for managing image quality in a laser-based imaging system is provided. Laser light sources are organized into two or more groups, and optical output power of a light source group containing an under-performing laser is matched to that of the under-performing laser, while the optical output power of the light sources in the remaining groups is not. The output of the laser light sources in each group is interleaved with the output of the laser light sources in the other groups, so that perceptual uniformity of a displayed image is maintained when the display is viewed from an appropriate viewing distance.