Phase Modulation Device Disclination Control
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Solution Overview
Problem
In phase modulation devices using liquid crystal elements, disclination occurs due to potential differences between pixel and peripheral regions, leading to crosstalk and signal light reflection at unintended angles, affecting output port accuracy.
Innovation Solution
A phase modulation device with an image data generator, gradation data generator, and adjustment voltage controller applies sawtooth waveform voltage patterns to pixel electrodes and adjacent adjustment electrodes, ensuring equal voltage values to reduce potential differences and prevent disclination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a peripheral region is formed outside the pixel region, then the liquid crystal element structure is complete, but potential difference causes disclination and signal light reflection at unintended angles
Solution Approach 1:
The patent applies equipotentiality by connecting the peripheral region to the pixel region through a connection portion that maintains equal potential. This eliminates the potential difference between regions, preventing disclination and ensuring signal light reflects only at the intended angle, thus resolving the contradiction between structural completeness and reflection accuracy.
2Adaptability or versatility
If voltage pattern is applied to pixel electrodes, then phase modulation function is achieved, but potential difference with peripheral region causes disclination
Solution Approach 1:
The connection portion acts as an intermediary element between the pixel region and peripheral region. It mediates the potential difference by providing a gradual transition zone that maintains electrical continuity while preventing abrupt potential changes, thus eliminating disclination while preserving the phase modulation function.
3Ease of operation
If lateral electric field is strong, then phase modulation control is effective, but disclination occurs and generation area is widened
Solution Approach 1:
The patent changes the electrical parameter distribution by introducing a connection portion with intermediate voltage characteristics. This parameter change creates a gradual potential transition that reduces the lateral electric field strength at the boundary, preventing disclination while maintaining effective phase modulation control in the pixel region.
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 solution effectively suppresses disclination, ensuring signal light is reflected at the target inclination angle, reducing crosstalk and improving output port accuracy.
Implementation Method 1
A refractive index of a liquid crystal on each pixel electrode changes by controlling a voltage applied to the liquid crystal for each pixel electrode. The phase velocity of the signal light is controlled for each pixel by changing the refractive index of the liquid crystal on each pixel.
Implementation Method 2
The LCOS element can incline a wavefront of the signal light by changing the phase velocity stepwise for each pixel. The LCOS element can control an inclination angle of the wavefront of the signal light according to a rate of change of the phase velocity. That is, the LCOS element functions as a phase modulation element that reflects the signal light in a predetermined direction by changing the phase velocity for each pixel.
Implementation Method 3
Disclination may occur due to a potential difference between the pixel region and the peripheral region adjacent to the pixel region. The adjustment voltage controller applies an adjustment voltage having a same voltage value as a driving voltage applied to a pixel electrode of a pixel block adjacent to the first adjustment electrode, to the first adjustment electrode.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The phase modulation device (1) includes an image data generator (2), a gradation data generator (3), an adjustment voltage controller (5), and a reflective liquid crystal element (10). The image data generator (2) generates image data (DD) corresponding to a distribution of phase change amount or a distribution of phase velocity. The gradation data generator (3) generates gradation data (DS) corresponding to each pixel. The reflective liquid crystal element (10) includes a pixel region (21) having a plurality of pixel blocks (25), and an adjustment electrode (41). The adjustment voltage controller (5) applies an adjustment voltage (AV) having a same voltage value as a driving voltage (DV) applied to a pixel electrode (24) of the pixel block (25) adjacent to the adjustment electrode (41).