Liquid Crystal Variable Drive Voltage for Optical Bounce Reduction
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Solution Overview
Problem
Liquid crystal devices, particularly polarization switches in LCDs, experience optical bounce due to transitions between driven and relaxed voltage states, leading to delayed responses and unwanted optical effects, which are more pronounced in 3D displays.
Innovation Solution
Implementing a variable drive voltage system that reduces the voltage from a driven state to a relaxed state over a period greater than 1 μs but within 20 ms, and providing pulses of limited duration to the light source, allowing for independent timing of voltage changes across segments, thereby minimizing optical bounce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage is reduced quickly from driven state to relaxed state, then the transition time is shortened, but optical bounce increases causing delayed response and unwanted optical effects
Solution Approach 1:
The patent applies dynamics by making the voltage transition time variable rather than fixed. The system dynamically adjusts the voltage reduction time based on the specific operational context, allowing optimization between speed and optical stability for different display conditions and frame rates.
Solution Approach 2:
The patent changes the temporal parameter of voltage application by extending the voltage reduction time to greater than 1 μs. This parameter modification directly addresses the optical bounce issue by allowing the liquid crystal molecules more time to transition smoothly, thereby improving optical response stability while maintaining acceptable transition speed.
2Reliability
If the voltage reduction time is extended to reduce optical bounce, then optical stability improves, but the transition time increases potentially affecting frame rate
Solution Approach 1:
The patent applies partial action by extending the voltage reduction time only when and where needed to sufficiently reduce optical bounce, rather than uniformly across all operations. The timing is optimized to provide just enough extension to achieve optical stability without unnecessarily sacrificing frame rate performance.
3Device complexity
If fixed voltage timing is used for all segments, then device complexity is reduced, but adaptability to different display conditions decreases
Solution Approach 1:
The patent applies segmentation by dividing the display into multiple independently controllable segments. Each segment can have its voltage timing independently adjusted based on local requirements, enabling the system to adapt to different display conditions while maintaining a relatively simple overall device architecture through modular control.
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 reduces optical bounce, allows for more stable transitions, and enhances image quality by increasing the duration of steady states, reducing ghosting and improving contrast in both 2D and 3D displays.
Implementation Method 1
polarization switches may include liquid crystals (LCs) that twist and rotate in response to a voltage, thereby affecting light transmittance
Implementation Method 2
Polarization switches may be utilized in conjunction with a light source to control how much light is transmitted to the display at a given time
Data Source
AI summary
A voltage may be provided to a liquid crystal addressable element as part of a liquid crystal device. The provided voltage may be reduced from a driven state to a relaxed state in a time period greater than 1 μs. The reduction may further be performed in less than 20 ms. The liquid crystal device may be a polarization switch, which in some embodiments may be a multi-segment polarization switch. In one embodiment, pulses of limited duration of a light source may be provided to the polarization switch. The manner of voltage reduction may reduce optical bounce of the liquid crystal device and may allow one or more of the pulses of the light source to be shifted later in time.