MOEMS Mirror for Stereolithography Optical Unit
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Solution Overview
Problem
Stereolithography machines using galvanometric mirrors are complex, costly, and unsuitable for small series applications due to alignment requirements, high maintenance needs, and bulkiness, which limits their use in producing objects with precise control over light intensity and speed.
Innovation Solution
A stereolithography machine employing a micro-opto-electro-mechanical system (MOEMS) with a single miniaturized mirror capable of independent rotation on two axes, eliminating the need for mirror alignment and reducing the number of mechanical components, thus simplifying production and maintenance while providing precise control over light intensity and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If galvanometric mirrors are used to direct the light beam, then the beam can be moved quickly and light intensity can be modulated, but the device becomes complex, costly, and bulky requiring alignment procedures
Solution Approach 1:
The patent combines two separate galvanometric mirrors into a single micro-electromechanical mirror that can rotate around two orthogonal axes. This single mirror integrates the functionality of both mirrors while eliminating the need for alignment between multiple components, thereby reducing device complexity while maintaining fast beam movement capability
Solution Approach 2:
The patent replaces the mechanical galvanometric mirror system with a micro-electromechanical system (MEMS) mirror. This substitution eliminates the need for complex mechanical alignment procedures and reduces the number of mechanical components, thereby simplifying the optical unit while preserving the ability to quickly direct the light beam
2Reliability
If galvanometric mirrors are used, then reliable beam direction control is achieved, but maintenance needs increase and production costs rise
Solution Approach 1:
The patent merges the functionality of two galvanometric mirrors into a single MEMS mirror with dual-axis rotation capability. This reduction in component count directly lowers production costs and assembly complexity while maintaining reliable beam direction control through the integrated mirror system
Solution Approach 2:
The patent substitutes traditional mechanical galvanometric mirrors with a micro-electromechanical system mirror. This substitution reduces production costs by eliminating complex mechanical assemblies and alignment requirements, while the MEMS technology provides comparable or superior reliability in beam direction control
3Productivity
If multiple mirrors are used to cover the reference surface, then the entire surface can be lit simultaneously, but the machine dimensions increase
Solution Approach 1:
The patent combines multiple mirror functions into a single compact MEMS mirror that can rotate around two orthogonal axes. This single mirror can sweep the light beam across the entire reference surface sequentially, maintaining productivity while significantly reducing the machine volume compared to systems using multiple large mirrors
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
The MOEMS-based system reduces production and maintenance costs, allows for smaller machine dimensions, and enables faster processing times, making it suitable for small series applications and even portable use without compromising precision or light modulation capabilities.
Implementation Method 1
said micro-opto-electro-mechanical system comprises a miniaturized mirror capable of rotating, around two orthogonal axes which are incident on each other, around which said mirror is arranged to reflect said radiation so as to direct it towards any point on said reference surface
Implementation Method 2
A stereolithography machine of the known type comprises a container that contains a fluid substance, generally a light-sensitive resin in the liquid or paste state. The machine comprises also a source, generally of the luminous type, which emits radiation suited to solidify the fluid substance
Data Source
Figure 1
Figure 2
AI summary
Stereolithography machine (1) comprising: a container (2) for a fluid substance (14); a source (3) of predefined radiation (3a) suited to solidify the fluid substance (14); an optical unit (4) suited to direct the radiation (3a) towards a reference surface (5) in the fluid substance (14); a logic control unit (6) configured to control the optical unit (4) and/or the source (3) so as to expose a predefined portion of the reference surface (5). The optical unit (4) comprises a micro-opto-electro-mechanical system (MOEMS) (7) provided with a mirror (8) associated with actuator means (7a) for the rotation around at least two rotation axes (X, Y) incident on and independent of each other, arranged so that it can direct the radiation (3a) towards each point of the reference surface (5) through a corresponding combination of the rotations around the two axes (X, Y).