Sub-pixel Shifting for Solid Imaging Edge Smoothness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing three-dimensional solid imaging techniques face challenges in achieving high resolution and smooth edge formation due to the limitations of digital light projectors with fixed pixel numbers, leading to inaccurate feature placement and rough edges in objects built layer-by-layer.
Innovation Solution
A pixel shifting technique is employed, where the projected image is aligned to the correct feature position and multiple exposures are made with sub-pixel displacement, using an algorithm to control the digital light projector, allowing for high-resolution imaging and edge smoothness by rotating transparent planes or moving the projector and cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If digital light projectors with fixed pixel numbers are used for layer-by-layer three-dimensional object fabrication, then device complexity is reduced and cost is lowered, but manufacturing precision and edge smoothness deteriorate due to coarse resolution and inaccurate feature placement
Solution Approach 1:
The patent applies dynamics by making the projected image movable through sub-pixel displacement. Instead of using a static fixed-pixel projector, the system dynamically shifts the projected image by fractional pixel amounts between exposures, allowing the same projector to achieve variable effective resolution and accurate feature placement without changing the physical projector hardware.
Solution Approach 2:
The patent introduces a temporal dimension to the projection process by taking multiple exposures at different sub-pixel positions. This transforms a two-dimensional spatial limitation (fixed pixel grid) into a three-dimensional solution space by adding the time dimension, where multiple exposures at different positions combine to achieve higher effective resolution.
2Manufacturing precision
If multiple exposures with sub-pixel displacement are implemented to improve resolution and edge smoothness, then manufacturing precision improves, but productivity decreases due to increased exposure time and process complexity
Solution Approach 1:
The patent applies periodic action by using a sequence of discrete exposures at different sub-pixel positions rather than continuous projection. The system periodically shifts the image by fixed sub-pixel increments and takes exposures at each position, creating a rhythmic pattern of shift-expose-shift-expose that systematically builds up the high-resolution image.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and pre-positioning the image at each sub-pixel location before exposure. The system determines all necessary shift positions and image data in advance, then executes the exposure sequence without real-time adjustments, reducing overhead and improving efficiency.
3Manufacturing precision
If the projected image is shifted to achieve correct feature position and edge smoothness, then manufacturing precision improves, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent replaces mechanical image shifting mechanisms (such as moving mirrors or translating the projector) with digital image processing. Instead of physically moving components, the system uses software to generate shifted image versions and controls the projector to display these digitally shifted images, eliminating complex mechanical control systems while achieving the same sub-pixel positioning accuracy.
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 results in a low-cost, high-resolution three-dimensional object fabrication method with accurate feature placement and smooth edges, overcoming the limitations of fixed pixel projectors and enhancing the resolution and smoothness of three-dimensional objects.
Implementation Method 1
visible light to initiate the photopolymerization reaction to cure the photopolymer build material
Data Source
AI summary
A solid imaging apparatus and method employing sub-pixel shifting in multiple exposures of the digitally light projected image of a cross-section of a three-dimensional object on a solidifiable liquid medium. The multiple exposures provide increased resolution, preserving image features in a three-dimensional object and smoothing out rough or uneven edges that would otherwise be occur using digital light projectors that are limited by the number of pixels in an image projected over the size of the image. Algorithms are used to select pixels to be illuminated within the boundary of each image projected in the cross-section being exposed.