Microlens Array Diffuser for Laser Scanning Display Interference
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Solution Overview
Problem
In head-up display (HUD) systems, light interference between neighboring pixels results in brightness variations across the projected image, degrading image quality due to speckle noise, Moire patterns, or other interference patterns, which are not effectively addressed by existing technologies.
Innovation Solution
A light beam scanning system that includes a 2D scanner and a diffuser screen with a microlens array, where the controller synchronizes pixel light beam transmission times with the scanner's movement to ensure each beam is incident on a single microlens, preventing interference by matching beam trajectories with the microlens array geometry, and optionally using a polarization mask to further reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a diffuser screen is used to expand beam width, then uniformity of illumination is improved, but light interference between neighboring pixels increases
Solution Approach 1:
The diffuser screen is segmented into multiple diffuser elements arranged in an array, where each diffuser element corresponds to a specific pixel light beam. This segmentation allows each element to independently control and expand its associated beam width without causing light interference with neighboring beams, thereby maintaining uniform illumination while preventing harmful interference patterns.
2Area of stationary object
If beam width is expanded to improve eyebox size, then field of view is improved, but brightness variations due to interference increase
Solution Approach 1:
The diffuser screen is divided into multiple independent diffuser elements, each responsible for expanding a specific pixel light beam. This segmentation enables controlled beam expansion that increases eyebox size while preventing interference between adjacent beams, thereby avoiding brightness variations and maintaining uniform illumination across the expanded field of view.
3Manufacturing precision
If microlens array is used to focus light, then image clarity is improved, but light interference patterns such as Moire patterns occur
Solution Approach 1:
The microlens array is segmented into multiple independent microlens elements, where each microlens corresponds to a specific pixel light beam. This segmentation ensures that each microlens focuses its associated beam independently without causing Moire patterns or other interference patterns, thereby maintaining image clarity while eliminating harmful interference.
4Speed
If 2D scanner steers light beams rapidly, then scanning speed is improved, but synchronization precision with pixel light beam transmission becomes difficult
Solution Approach 1:
The controller is configured to trigger the generation of pixel light beams in advance based on the known scanning pattern and timing of the 2D scanner. By calculating and pre-scheduling the transmission times of pixel light beams to correspond with the scanner's position, the system achieves precise synchronization even at high scanning speeds, thereby maintaining both speed and synchronization precision.
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 solution significantly reduces light interference, preventing brightness variations and enhancing the quality of the projected image by ensuring each pixel light beam is focused on a single microlens, thereby improving the overall image clarity and reducing unwanted patterns.
Implementation Method 1
the diffuser screen comprises a microlens array comprising a plurality of microlenses arranged in a 2D array
Implementation Method 2
the diffuser screen comprises a polarization mask comprising a polarization array, wherein the polarization array comprises a plurality of polarization components arranged in a second 2D array
Data Source
AI summary
A light beam scanning system includes a light transmitter configured to generate pixel light beams corresponding to an image and transmit the pixel light beams on an optical path; a two-dimensional (2D) scanner arranged on the optical path and configured steer the pixel light beams according to a 2D scanning pattern; a diffuser screen arranged on the optical path downstream from the 2D scanner and configured to expand a beam width of each pixel light beam of the plurality of pixel light beams to generate divergent pixel light beams, wherein the diffuser screen includes a microlens array having a plurality of microlenses arranged in a 2D array; and a controller configured to synchronize transmission times of the plurality of pixel light beams with a movement of the 2D scanner such that trajectories of the plurality of pixel light beams are matched with a geometry of the microlens array.