Risley Prism Laser Steering for High-Resolution SLA Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stereolithography (SLA) 3D printers face limitations in achieving higher resolution and larger build sizes due to their fixed lateral resolution and build size constraints.
Innovation Solution
The use of Risley prisms or equivalent opto-mechanical solutions for laser beam steering, combined with cycloidal diffractive waveplates, allows for precise angular control of UV light to achieve higher resolution and larger build sizes by steering the laser beam around the print area without the need for mechanical housing, enabling improved lateral and vertical resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spatial light modulator (SLM) is used to generate a pattern in the liquid resin, then the lateral build size is fixed at 2.7''×4.7'' for a 2k format printer, but higher resolution and larger build sizes are desired
Solution Approach 1:
The patent replaces the static SLM projection system with a dynamic laser beam scanning system using Risley prisms. The laser beam is steered across the build area by rotating the Risley prisms, enabling the pattern to be dynamically positioned anywhere within a larger build volume rather than being fixed to the SLM active area. This dynamic scanning approach decouples resolution from build size constraints.
Solution Approach 2:
The patent substitutes the electro-optical SLM mechanism with an opto-mechanical laser scanning system. Instead of modulating light at a fixed plane using liquid crystals or micro-mirrors, the system uses mechanically rotated Risley prisms to steer a laser beam, replacing the SLM's mechanical/electrical modulation approach with pure optical steering.
2Area of stationary object
If the lateral build size is increased, then the resolution decreases, but both larger build size and higher resolution are needed
Solution Approach 1:
The laser scanning system with Risley prisms enables dynamic control of beam position and size independently. The system can maintain a small laser spot size (for high resolution) while scanning across a large build area by coordinating the rotation of the Risley prisms with the build platform motion, decoupling spot size from scan range.
Solution Approach 2:
The patent changes the optical parameters by using a laser source with specific wavelength and collimation properties, combined with Risley prism geometry optimization. This allows the laser spot size to be maintained at a small scale (enabling 6 μm resolution) while the scanning range is extended to cover larger build volumes through coordinated motion control.
3Device complexity
If traditional beam steering mechanisms are used, then complex mechanical housing and motor control are required, but simpler and more precise control is desired
Solution Approach 1:
The patent replaces complex mechanical beam steering mechanisms (such as galvanometer mirrors or rotary stages with multiple axes) with a compact Risley prism pair system. The Risley prisms can be rotated using simple motors to precisely control the beam angle, eliminating the need for complex mechanical housing and multi-axis motor control systems while achieving superior angular precision.
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 solution provides approximately 6 μm lateral resolution and 25 μm layer thickness over a substantial region, expanding the capabilities of SLA 3D printers to larger production sizes while reducing the demand on rotation stages and motor control, and eliminating chromatic aberration.
Implementation Method 1
A shutter selectively allows the reduced laser beam to pass through a pair of Risley elements to increase an angular offset from a longitudinal axis of the optical steering system to the print layer
Implementation Method 2
The laser beam is reduced in size by a polarization grating point image to a reduced size laser beam
Implementation Method 3
stereolithography (SLA) 3D printers... hardening it with the ultra-violet (UV) light that illuminates the SLM
Data Source
AI summary
A resin curing system provided by stereolithography (SLA) three-dimensional (3D) printer includes a pair of Risley prism for optical steering of laser energy to achieve improved resolution.