Spatial Light Modulator Driving With Phase Offsets Against Pixel Sticking
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Solution Overview
Problem
Spatial light modulators used in holographic displays are prone to performance degradation due to imbalanced driving, which can lead to pixel sticking and reduced longevity, especially when displaying holograms rather than real images.
Innovation Solution
Applying a changing phase offset to each pixel of the spatial light modulator, ensuring the same offset is applied simultaneously to all pixels at different times, thereby randomizing grey levels and minimizing imbalances in driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a spatial light modulator is driven to display holograms for prolonged periods, then the device can maintain continuous operation, but performance degradation occurs due to imbalanced driving causing pixel sticking
Solution Approach 1:
The patent applies periodic frame inversion to the spatial light modulator, alternating between positive and negative voltage polarities for each frame displayed. This periodic reversal prevents DC bias accumulation and ensures balanced driving conditions, thereby preventing pixel sticking and maintaining performance stability during prolonged continuous operation
Solution Approach 2:
The patent dynamically changes the voltage polarity parameter from frame to frame, switching between positive and negative values. This parameter variation ensures that the spatial light modulator experiences balanced electrical stress over time, preventing degradation while maintaining continuous operational capability
2Reliability
If field inversion is applied to balance driving voltage, then pixel sticking is reduced, but the complexity of the driving scheme increases
Solution Approach 1:
The frame inversion technique implements a simple periodic alternation between positive and negative voltage frames, providing reliable pixel stability through regular polarity reversal while maintaining relatively simple implementation through systematic frame alternation
Solution Approach 2:
The patent changes the voltage polarity parameter in a systematic alternating pattern between frames, achieving pixel stability through parameter variation while keeping the driving scheme manageable through regular, predictable alternation rather than complex adaptive control
3Measurement precision
If the spatial light modulator displays holograms with static phase patterns, then the holographic reconstruction quality is maintained, but imbalanced driving causes performance degradation over time
Solution Approach 1:
By periodically inverting the voltage polarity of each frame while maintaining the holographic phase pattern integrity, the system preserves reconstruction quality through accurate phase modulation while simultaneously preventing performance degradation through balanced electrical driving conditions
Solution Approach 2:
The patent varies the voltage polarity parameter between frames while preserving the relative phase relationships that define the holographic pattern, thereby maintaining reconstruction precision while extending operational longevity through balanced driving
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 maintains the performance characteristics of the spatial light modulator over extended use without affecting the quality of holographic reconstructions, reducing the tendency of pixel sticking and preserving image quality.
Implementation Method 1
Light modulation may be achieved using electrically-addressable liquid crystals
Implementation Method 2
arranged to modulate the amplitude and/or phase of incident light
Implementation Method 3
apply a series of phase offsets to each pixel of the spatial light modulator such that the same first value of phase offset is applied to each pixel at a first time, and the same second value of phase offset is applied to each pixel at a second time
Data Source
AI summary
There is provided a driver for a spatial light modulator comprising a plurality of pixels. The driver is configured to receive a hologram of a picture and drive the spatial light modulator to display the hologram on a group of pixels of the plurality of pixels. The driver is further configured to apply a series of phase offsets to the spatial light modulator displaying the hologram, wherein each phase offset of the series of phase offsets is applied to each pixel of the group of pixels for a respective predetermined period of time.