Light Valve Gap Maintenance Using Surface Tension
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Solution Overview
Problem
High power laser systems used in additive manufacturing face challenges with maintaining uniform gap thickness between substrates and liquid crystal layers, leading to non-uniform light valve performance and potential stress-induced birefringence.
Innovation Solution
The use of thin, pliable substrates with closely matched coefficients of thermal expansion (CTE) and the incorporation of laser transparent aperture support structures within the liquid crystal layer to maintain a uniform gap thickness, utilizing surface tension and aperture support structures to achieve and maintain gap uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick substrates are used to maintain rigidity and gap thickness in larger format light valves, then the substrates can provide inherent self-support, but they cannot readily compensate for stress, warping or deformation, causing non-uniform gap thickness across the aperture
Solution Approach 1:
The patent uses thin, flexible substrates instead of thick rigid ones. These thin substrates can deform to compensate for stress and warping, maintaining uniform gap thickness across the aperture. The flexibility allows the substrates to conform and self-adjust, solving the contradiction between rigidity and uniformity.
Solution Approach 2:
The patent changes the key parameter of substrate thickness from thick to thin, fundamentally altering the mechanical properties. This parameter change enables the substrates to be flexible enough to compensate for deformation while maintaining gap uniformity, resolving the contradiction between strength and precision.
2Manufacturing precision
If thin, pliable substrates are used, then stress compensation and gap uniformity are improved, but substrate strength and rigidity are reduced
Solution Approach 1:
The patent merges multiple thin substrates with closely matched CTEs into a composite structure. This combination provides both flexibility for stress compensation and sufficient overall strength, resolving the contradiction between thinness and rigidity.
Solution Approach 2:
The patent uses composite substrate structures with materials having closely matched coefficients of thermal expansion. This composite approach maintains gap uniformity through flexibility while providing adequate strength through material combination.
3Stability of the object's composition
If substrates with closely matched CTEs are used, then thermomechanical stress is reduced, but material selection and manufacturing complexity increase
Solution Approach 1:
The patent uses substrates with homogeneous properties - specifically, materials with closely matched coefficients of thermal expansion. This homogeneity reduces thermomechanical stress by ensuring uniform expansion and contraction behavior across the substrate stack, simplifying the stress management aspect of manufacturing.
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 approach enhances the uniformity and stability of the light valve performance, reduces thermomechanical stress, and extends the device's operational lifetime by maintaining a consistent gap thickness even under dynamic load conditions.
Implementation Method 1
A liquid crystal layer is positioned between a first and a second substrate. The liquid crystal layer may provide a surface tension that helps maintain a uniform gap thickness between the first and the second substrate.
Data Source
AI summary
A light valve can include a liquid crystal layer having a first and a second side. A first substrate is positioned in contact with the first side of the liquid crystal layer, with the first substrate having a first semiconductor layer. A second substrate is positioned in contact with the second side of the liquid crystal layer, with the second substrate having a second semiconductor transparent electrode layer and a second semiconductor layer. A plurality of laser transparent aperture support structures are positioned within the liquid crystal layer to contact both the first and the second substrate to generate a stable uniform gap under the force from the liquid crystal surface tension applied to substrate that are thin and compliant.