Micro-Truss Fabrication via Bottom-Up Photopolymerization
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Solution Overview
Problem
Current methods for fabricating micro-truss structures are primarily top-down approaches, and there is a need for a system that can form these structures from the bottom up, allowing for more versatile and efficient fabrication techniques.
Innovation Solution
A system comprising a reservoir with a liquid photomonomer, a partially transparent mask at the bottom with apertures, a release layer to prevent adhesion, and a collimated light source with mirrors to direct light from multiple angles, forming self-guided photopolymer waveguides within the reservoir, which polymerize to create micro-truss structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If top-down fabrication method is used, then manufacturing process is simple, but structure growth direction control is limited
Solution Approach 1:
The patent inverts the conventional top-down fabrication approach by implementing a bottom-up growth method. Instead of forming micro-truss structures by illuminating liquid photomonomer from above through photomasks, the system illuminates from below through a transparent reservoir bottom, allowing structures to grow upward. This inversion enables precise control over growth direction while maintaining fabrication feasibility through the transparent reservoir design and multi-angle light delivery system.
2Device complexity
If light illumination is from single direction, then device complexity is low, but waveguide formation precision is insufficient
Solution Approach 1:
The patent transitions from single-direction (one-dimensional) light illumination to multi-directional (three-dimensional) light delivery by positioning light sources at multiple angles around the reservoir. This dimensional expansion allows collimated light beams to converge at precise focal points within the photomonomer, enabling accurate waveguide formation and micro-truss structure fabrication with controlled geometry and orientation that cannot be achieved with single-direction illumination.
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
Enables the formation of micro-truss structures with self-guided waveguide members from the bottom up, offering greater control and flexibility in structure design and growth direction, overcoming limitations of traditional top-down methods.
Implementation Method 1
A reservoir holds a volume of a liquid photomonomer configured to polymerize to form a photopolymer when exposed to suitable light such as ultraviolet light
Implementation Method 2
A plurality of mirrors may reflect the light from a single source of collimated light to form a plurality of collimated beams, that illuminate the photomonomer in the reservoir, through the mask, from a corresponding plurality of directions
Implementation Method 3
the initial area of polymerization, such as a small circular area, will 'trap' the light and guide it to the tip of the polymerized region, further advancing that polymerized region
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A system for fabricating micro-truss structures. A reservoir holds a volume of a liquid photomonomer configured to polymerize to form a photopolymer when exposed to suitable light such as ultraviolet light. A mask at the bottom of the reservoir includes a plurality of apertures. Light enters the reservoir through each aperture from several directions, forming a plurality of self -guided photopolymer waveguides within the reservoir. The light is supplied by one or more sources of collimated light. A plurality of mirrors may reflect the light from a single source of collimated light to form a plurality of collimated beams, that illuminate the photomonomer in the reservoir, through the mask, from a corresponding plurality of directions, to form a micro-truss structure including a plurality of self-guided waveguide members.