Tiled Display Pixel Shift for Seamless Laser Scanning
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Solution Overview
Problem
Tiled display systems using rotating polygon mirrors for laser scanning often exhibit a 'Christmas tree' or 'stair step' effect when displaying moving objects due to time delays between scanning different portions of the image across multiple tiles, leading to a broken image appearance.
Innovation Solution
Implementing a method to delay the display of image portions on successive rows of tiles such that the top portion of a first tile is scanned immediately after the bottom portion of an adjacent tile is scanned, using a central controller to provide output signals with a predetermined time delay, thereby synchronizing the image display across tiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a rotating polygon mirror is used to scan laser beams across the image-generating surface, then high-speed laser imaging is achieved, but a substantial time delay occurs between scanning the first portion and the final portion of the 2-dimensional surface
Solution Approach 1:
The display system is divided into multiple independently controllable tiles, each with its own laser scanning system. This segmentation allows different portions of the display to be scanned and updated independently, enabling the top portion to be scanned immediately after the bottom portion without waiting for sequential completion across the entire display surface.
Solution Approach 2:
Image data is pre-processed and distributed to individual tiles in advance, with each tile receiving the complete image data set simultaneously. This preliminary action allows each tile to begin scanning immediately without waiting for sequential data transmission, eliminating the time delay between scanning different portions.
2Area of stationary object
If tiles are arranged in a tiled display system to form a large display, then the display area is increased, but a 'Christmas tree' or 'stair step' effect appears when displaying moving objects
Solution Approach 1:
Multiple tiles are merged into a single coordinated display system with unified control. The central controller synchronizes the scanning operations of all tiles, and the laser scanning system treats the entire tiled surface as a single continuous scanning area, eliminating visible discontinuities between individual tiles.
Solution Approach 2:
The scanning parameters (such as scan timing, beam position, and synchronization delays) are dynamically adjusted for each tile based on its position in the array. This parameter optimization ensures that images displayed across multiple tiles appear seamless and properly aligned, removing the stair step effect.
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 eliminates the 'stair step' effect by ensuring that the image appears seamless when moving objects are displayed across multiple tiles, as the top portion of each tile is illuminated only after the bottom portion of the adjacent tile is illuminated, preventing visible discontinuities.
Implementation Method 1
A laser beam incident on one of the reflective surfaces is directed to the image-generating surface, and as the polygon rotates, the incident laser beam sweeps across the image-generating surface
Implementation Method 2
as each subsequent reflective surface rotates through the incident laser beam, the beam is directed to and sweeps across a different location on the image-generating surface, thereby performing 2-dimensional scanning
Data Source
AI summary
The display of a portion of an image in successive rows of display tiles in a tiled display system are delayed, so that the top portion of a first display tile is illuminated immediately after the bottom portion of a second display tile is illuminated, where the second display tile is adjacent to and above the first display tile. This removes the appearance of a broken up image when the image moves across the display tiles in a direction somewhat parallel to the direction of raster scanning. In this way, a raster scanning tiled display system does not produce a stair-step effect even though the top and bottom portion of an image on a tile in the tiled display system is raster-scanned at different times.