Aligning Pixelated Light Engines Using Calibration Targets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stereolithography systems with spatial light modulators are limited by the pixel count, hindering the creation of larger and higher resolution three-dimensional articles due to alignment challenges and distortion issues in projecting pixel columns onto a target.
Innovation Solution
A three-dimensional printing system that includes a substrate with a calibration target and multiple projection modules, where a radiation sensor and controller align the projection modules by measuring light intensity patterns to accurately position pixel columns along the X and Y axes, and adjust for theta-Z angular alignment, using elongate light modulating bars to compensate for distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pixel count of the spatial light modulator is increased to form larger and higher resolution articles, then the resolution and size capability improve, but alignment precision deteriorates due to increased complexity in positioning multiple projection modules
Solution Approach 1:
The system uses a radiation sensor to detect light intensity patterns from the calibration target and feeds this information back to the controller. The controller analyzes the intensity patterns and automatically adjusts the positioning of projection modules to achieve precise alignment, eliminating manual alignment errors even with increased pixel counts
Solution Approach 2:
The patent replaces manual mechanical alignment procedures with an automated optical measurement and control system. The radiation sensor detects light intensity patterns, and the controller processes this data to automatically position projection modules, substituting mechanical alignment operations with automated optical-mechanical integration
2Area of stationary object
If multiple projection modules are used to increase the build field size, then the article size capability improves, but alignment complexity increases making it difficult to maintain consistent positioning across modules
Solution Approach 1:
The calibration target with its specific pattern serves multiple functions: it enables alignment of multiple projection modules, provides reference for intensity pattern detection, and facilitates automated positioning. This single multi-functional element simplifies the alignment process across all projection modules
Solution Approach 2:
The radiation sensor continuously monitors light intensity patterns from the calibration target, providing feedback to the controller. This feedback mechanism enables real-time adjustment and maintains consistent positioning across all projection modules, reducing alignment complexity despite having multiple modules
3Area of stationary object
If projection modules are positioned closer together to cover the same area, then the system compactness improves, but alignment errors increase due to overlapping image fields
Solution Approach 1:
The radiation sensor detects light intensity patterns in the overlapping regions of image fields and feeds this information back to the controller. The controller uses this feedback to calculate and apply precise positioning adjustments, eliminating alignment errors that would otherwise occur in overlapping regions
Solution Approach 2:
The system replaces manual alignment procedures with automated control based on optical intensity pattern detection. The controller processes sensor data and automatically adjusts projection module positions, substituting mechanical alignment operations with automated feedback-controlled positioning
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 method enables precise alignment and increased resolution by accurately positioning pixel columns, enhancing the ability to form larger and higher quality three-dimensional articles by minimizing alignment errors and distortions, thereby overcoming the limitations of existing systems.
Implementation Method 1
A radiation sensor and controller align the projection modules by measuring light intensity patterns
Implementation Method 2
One class of stereolithography systems utilizes light engines based on spatial light modulators such as arrays of micromirrors
Implementation Method 3
The stereolithography system forms a three dimensional (3D) article of manufacture by selectively curing layers of the photocurable resin
Data Source
AI summary
A three-dimensional printing system is for fabricating or manufacturing a three-dimensional article. The three-dimensional printing system includes a substrate, a light engine, a radiation sensor, and a controller. The substrate has a surface positioned proximate to a build field. The surface supports a calibration target which includes or defines elongate light modulating bars disposed at two different orientations and including a Y-bar aligned with a Y-axis and an X-bar aligned with an X-axis. The light engine includes a plurality of projection modules including at least a first projection module and a second projection module. The first projection module configured to project an array of pixels onto a first image field. The second projection module configured to project an array of pixels onto a second image field.