Wire Grid Polarizers for Stereolithography LCD Systems
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Solution Overview
Problem
Current LCD systems for stereolithography face limitations in scaling up due to limited light intensity and wavelength range, leading to longer build times and restricted use with high-viscosity resins, as traditional film polarizers absorb light and have thermal issues.
Innovation Solution
Incorporating wire grid polarizers with nano-scale metal wires arranged orthogonally to enhance light polarization and transmission, allowing for higher intensity and lower wavelength light, reducing thermal issues and enabling faster curing times with a wider range of stereolithography feedstocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional film polarizers are used in LCD systems for stereolithography, then the system can operate with simpler structure, but light intensity is absorbed and thermal issues arise limiting scaling
Solution Approach 1:
The patent changes the fundamental parameter of polarizer construction from absorptive film material to reflective wire grid structure. This parameter change enables the system to handle higher light intensities and shorter wavelengths (down to 365 nm) without the thermal absorption limitations of traditional film polarizers, directly resolving the contradiction between structural simplicity and light intensity handling
Solution Approach 2:
The patent employs composite materials by combining transparent substrates with metal wire grids to create polarizers that reflect rather than absorb light. This composite approach maintains structural simplicity while enabling high light intensity operation and thermal resistance, solving the limitation of traditional film polarizers
2Ease of manufacture
If LCD systems use traditional film polarizers, then manufacturing is easier, but thermal damage occurs at high light intensities
Solution Approach 1:
The patent changes the operational parameter from light absorption to light reflection by using wire grid polarizers. This parameter change eliminates thermal damage to the polarizer itself while maintaining ease of manufacture through established wire grid fabrication techniques on transparent substrates
Solution Approach 2:
The patent converts the previously harmful light absorption by film polarizers into a beneficial reflective mechanism. By using wire grids that reflect polarized light rather than absorbing it, the system eliminates thermal damage while maintaining the polarization function, turning the thermal harm into a beneficial non-absorptive operation
3Volume of moving object
If larger build volumes are targeted in stereolithography, then part size increases, but build time increases due to serial laser scanning
Solution Approach 1:
The patent replaces the mechanical serial laser scanning system with an optical parallel projection system using LCD and wire grid polarizers. This substitution enables simultaneous curing of entire layers across large build volumes, dramatically reducing build time while maintaining large part sizes by eliminating the serial scanning bottleneck
4Productivity
If DMD or LCoS spatial light modulators are used for bottom-up printing, then print speed increases, but maximum part size is limited by chip size and light intensity
Solution Approach 1:
The patent creates a universal light patterning system using LCD and wire grid polarizers that can simultaneously achieve large area coverage and high light intensity. This multi-functional approach replaces the limited DMD/LCoS chips, enabling both fast printing and large part sizes by projecting high-intensity light across the entire build area without chip size constraints
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 use of wire grid polarizers increases light intensity and thermal resistance, enabling faster curing times and broader resin compatibility, allowing for larger print sizes without sacrificing feature size or increasing thermal damage.
Implementation Method 1
first wire grid polarizer array and a second wire grid polarizer array, each having a plurality of parallel arranged wires oriented orthogonally to one another for polarizing light
Implementation Method 2
The LCD display receives the polarized light having the first polarization and selectively rotates first portions of the polarized light to create second portions of light having a second polarization different from the first polarization
Implementation Method 3
A method of generating a patterned, two-dimensional (2D) light field for curing an optically curable material
Data Source
AI summary
The present disclosure relates to a liquid crystal display (LCD) system. The system in one example has a light source for generating unpolarized light, and an LCD screen arranged in a path of transmittance of the unpolarized light. First and second wire grid polarizers are arranged adjacent to the LCD screen and each have a plurality of nano-scale wires, with the first and second wire grid polarizers have differing polarizations. A pitch of each of the nano-scale wires is no larger than one-third a wavelength of the unpolarized light from the light source. The wire grid polarizers create, in connection with operation of the LCD screen, a 2D light mask suitable for initiating the polymerization of an optically curable material.