Digital LCOS Drive Schemes for Phase Ripple Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing digital LCOS displays face challenges with phase-mode operation due to phase ripple, phase switching noise, and phase instability, particularly in small pixels, which affect image quality and operational efficiency.
Innovation Solution
A drive scheme that optimizes the sequence and distribution of '1' and '0' bit-planes, adjusts voltages for each bit plane, and employs cyclical rotations to minimize phase ripple and noise, using varying Vpix and Vcom voltages to fine-tune performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital LCOS displays use rapid bit-plane switching to achieve gray-scale, then the eye can average the duty-cycle into equivalent gray-scale, but phase-mode displays experience phase ripple and instability because the eye cannot average out positional shifts
Solution Approach 1:
The patent applies dynamics by making the bit-plane sequence adaptive rather than fixed. The controller dynamically adjusts the sequence of bit-planes based on the specific phase-shift requirement, using different sequences for different phase levels to minimize phase ripple while maintaining stability
Solution Approach 2:
The patent changes the temporal distribution parameter of bit-plane transitions. By varying the timing and sequence of bit-plane switching based on the target phase-shift value, the system optimizes the LC response to reduce phase ripple and improve phase stability across different gray-scale levels
2Measurement precision
If digital displays use many bit-planes per frame to achieve gray-scale, then gray-scale precision improves, but the required external data rate increases
Solution Approach 1:
The patent segments the gray-scale representation into multiple bit-planes, but optimizes their distribution. Instead of using uniform bit-plane sequences, the system segments the temporal domain to write bit-planes at strategically spaced intervals, reducing the total number of transitions while maintaining gray-scale precision
Solution Approach 2:
The patent uses partial action by selectively activating bit-planes only when necessary. The controller determines the minimum number of bit-planes needed to achieve the desired phase-shift accuracy and uses only those, avoiding unnecessary transitions that would increase data rate requirements
3Device complexity
If digital LCOS displays operate from a fixed Vpix equivalent power supply, then the design is simplified, but phase ripple and non-linearities in the LC response cause phase errors
Solution Approach 1:
The patent applies dynamics by making the bit-plane sequence adaptive rather than fixed. The controller dynamically adjusts the sequence of bit-planes based on the specific phase-shift requirement, using different sequences for different phase levels to minimize phase ripple while maintaining stability
Solution Approach 2:
The patent changes the temporal distribution parameter of bit-plane transitions. By varying the timing and sequence of bit-plane switching based on the target phase-shift value, the system optimizes the LC response to reduce phase ripple and improve phase stability across different gray-scale levels
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 reduces phase ripple and noise, improves phase accuracy, and enhances the operating characteristics of digital LCOS displays, particularly in phase-mode operations.
Implementation Method 1
The variable voltages on these pixel electrodes in turn determine the response of the Liquid Crystal (LC) directly above each of these pixels and thus ultimately determine (for amplitude displays) the amount of polarization change for light reflected from that pixel, or (for phase displays) the amount of phase shift applied to the light reflected from that pixel
Data Source
AI summary
Systems and methods for improving operating characteristics of displays such as liquid crystal on silicon displays.