Dual-Panel LCD Killer Pattern Reduction via Dynamic Gray Scale
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Solution Overview
Problem
Dual-cell displays are prone to displaying degraded image quality known as 'killer patterns' due to differences in pixel values and contrast between the first and second liquid crystal panels, leading to issues like halos and unevenness when viewed from different angles.
Innovation Solution
A display device with a controller that determines the gray scale of the second liquid crystal panel's pixels by referencing conversion characteristics, adjusting the ratio of characteristics based on the difference between maximum and minimum pixel values, and applying image extension processing to reduce the risk of killer patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dual-cell display is used to achieve high contrast, then display contrast is improved, but killer pattern occurs causing degraded image quality
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gray scale conversion characteristics based on the difference between maximum and minimum pixel values. When the pixel value difference is large, a first conversion characteristic is used; when the difference is small, a second conversion characteristic is used. This dynamic parameter adjustment prevents killer patterns while maintaining high contrast display performance.
Solution Approach 2:
The patent implements dynamics by making the gray scale conversion characteristic selectable and changeable based on real-time pixel value analysis. The controller dynamically chooses between multiple conversion characteristics depending on the current image content's pixel value range, allowing the system to adapt to different display conditions and avoid killer patterns dynamically.
2Stability of the object's composition
If gray scale conversion is applied to second liquid crystal panel, then image consistency is improved, but complexity of control increases
Solution Approach 1:
The patent manages control complexity by changing parameters (selecting from predefined conversion characteristics) rather than implementing complex real-time calculations. The controller switches between different conversion characteristic sets based on simple pixel value range detection, achieving image consistency without excessive control complexity.
Solution Approach 2:
The patent applies preliminary action by pre-defining multiple conversion characteristics before actual display operation. These conversion characteristics are prepared in advance and stored, allowing the controller to simply select and apply the appropriate one based on current conditions, rather than calculating optimal conversion parameters in real-time.
Data Source
AI summary
A display device includes: a first liquid crystal panel; a second liquid crystal panel disposed on a back face of the first liquid crystal panel; and a controller, wherein the controller determines, based on a maximum value of a target pixel value of the display device and a surrounding pixel value of the display device and a minimum value of the target pixel value and the surrounding pixel value, a value of a gray scale of a target pixel of the second liquid crystal panel with reference to at least one of a plurality of conversion characteristics indicating characteristics different from each other as characteristics configured to convert the target pixel value into the value of the gray scale of the target pixel of the second liquid crystal panel.