Lattice-Walled Liquid Crystal Alignment for Sub-3μm Pixel Pitch
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Solution Overview
Problem
Current spatial light phase modulation elements have a minimum pixel pitch of 3.74 μm, which limits the achievable visual angle for holographic displays to 8.4°, falling short of the required 30° for practical applications. Additionally, achieving a pixel pitch of 1 μm or less is challenging due to issues with electric field leakage and liquid crystal alignment.
Innovation Solution
A liquid crystal alignment member for spatial light phase modulation is developed, featuring a lattice-shaped wall structure and a base layer with a groove, which allows for independent control of liquid crystal orientation in each pixel even at a pitch of 3 μm or less. The structure includes shape anisotropy in orthogonal directions, enabling effective alignment of liquid crystals without the need for additional alignment films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pixel pitch is reduced to increase the visual angle, then the observable image range is improved, but electric field leakage and liquid crystal alignment control deteriorate
Solution Approach 1:
The patent divides the pixel structure into separated microspaces using lattice-shaped wall structures. These walls segment the continuous liquid crystal layer into discrete regions, preventing electric field leakage between adjacent pixels while maintaining small pixel pitch. The segmentation creates physical barriers that isolate each pixel's electric field confinement.
Solution Approach 2:
The lattice-shaped wall structures serve as intermediary elements between adjacent pixels. These dielectric walls act as mediators that block electric field lines and elastic force propagation while allowing the liquid crystal to maintain its alignment function. The intermediary structure enables close pixel spacing without direct electric field interference.
2Area of stationary object
If the pixel pitch is reduced to increase the visual angle, then the observable image range is improved, but liquid crystal alignment control deteriorates
Solution Approach 1:
The patent applies local quality by creating shape anisotropy within each liquid crystal filling microspace. The microspaces have different dimensional characteristics (width vs. height) that locally guide liquid crystal alignment. This local geometric differentiation provides orientation control without requiring additional alignment films, even at reduced pixel pitch.
Solution Approach 2:
The patent transitions from two-dimensional planar alignment control to three-dimensional shape-based control. By creating microspaces with specific width-to-height ratios and introducing base grooves, the alignment control extends into the vertical dimension. This dimensional change provides stronger alignment regulation through the liquid crystal's interaction with the three-dimensional microspace geometry.
3Manufacturing precision
If additional alignment films are added to improve liquid crystal alignment, then the alignment control is improved, but the device structure becomes more complex
Solution Approach 1:
The lattice-shaped wall structures perform multiple functions simultaneously: they segment pixels to prevent electric field leakage, provide mechanical support, and guide liquid crystal alignment through shape anisotropy. This multi-functionality eliminates the need for separate alignment films, reducing structural complexity while maintaining alignment control.
Solution Approach 2:
The liquid crystal filling microspaces are designed to self-align the liquid crystal molecules through their inherent geometric shape anisotropy. The microspace geometry itself provides the alignment function without requiring external alignment films or additional processing steps. The structure serves its own alignment purpose through its dimensional characteristics.
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 proposed liquid crystal alignment member enables high-precision control of liquid crystal orientation, effectively blocking electric field leakage and elastic force propagation, thus achieving a spatial light modulation element with a pixel pitch of 3 μm or less. This results in a wider observable image range, making it suitable for advanced holographic and stereoscopic displays.
Implementation Method 1
blocking electric field leakage
Implementation Method 2
blocking elastic force propagation
Implementation Method 3
the liquid crystal-filling microspace includes shape anisotropy in a first axial direction and a second axial direction
Implementation Method 4
a base layer with a groove, in which a base groove extending to the second axial direction of the liquid crystal-filling microspace is formed
Implementation Method 5
since the liquid crystal molecules rotate due to dielectric anisotropy so that the direction of the electric power line and the longer axis are close to parallel
Implementation Method 6
spatial light phase modulation
Data Source
AI summary
A liquid crystal alignment member for spatial light phase modulation includes: a silicon substrate; a base portion including pixel electrodes arranged in a matrix with a period of 3 μm or less; a lattice-shaped wall structure configured by a dielectric material; a base layer connected to the lattice-shaped wall structure; and a plurality of liquid crystal-filling microspace separated from each other by the lattice-shaped wall structure, wherein the lattice-shaped wall structure is arranged at least between adjacent pixel regions; the liquid crystal-filling microspace includes a shape anisotropy in a first axial direction and a second axial direction in a plane parallel to the base portion; when WA is a space width of the first axial direction and WB is a space width of the second axial direction, WA is smaller than WB; and a base groove extending to the second axial direction is formed in the base layer.