Odd-Even Veil View for FFS Display Privacy
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Solution Overview
Problem
Fringe Field Switching (FFS) mode liquid crystal display devices struggle to provide a strong privacy effect when switching between public and private modes due to their near-linear off-axis to on-axis luminance response, which is not adequately masked by existing pixel splitting methods, resulting in insufficient obscuration of the on-axis image from off-axis viewers.
Innovation Solution
The implementation of enhanced image processing methods using control electronics to generate combined image data, where on-axis viewers perceive the main image and off-axis viewers perceive a side image, by processing main and side image data based on pixel type and location, without modifying the LC layer or pixel electrode geometry, utilizing a different look-up table for private mode to concentrate luminance differently across pixel types and rows, and applying a blurring filter to reduce image artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pixel splitting methods are used in FFS mode displays, then privacy effect is provided, but the privacy effect is insufficient due to near-linear off-axis to on-axis luminance response
Solution Approach 1:
The patent applies different image processing treatments to different pixel types (odd and even pixels) based on their specific luminance characteristics. By analyzing the off-axis to on-axis luminance response of each pixel type and applying customized pixel splitting algorithms, the system optimizes privacy effect for each pixel group, achieving stronger overall privacy performance than uniform processing methods
Solution Approach 2:
The patent modifies the image processing parameters specifically for FFS mode displays by adjusting the pixel splitting algorithm to account for the near-linear luminance response characteristic. The system changes the distribution ratios and luminance compensation parameters to maximize privacy effect despite the linear response, rather than using fixed parameters designed for displays with non-linear responses
2Object-affected harmful factors
If lenticular arrays or parallax barriers are added to modify pixel view angle properties, then stronger privacy effect is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical optical elements (lenticular arrays, parallax barriers) with an electronic image processing system. By using control electronics to manipulate pixel data and apply differential processing to odd and even pixels, the system achieves privacy effects previously only attainable with complex optical components, thereby reducing device complexity and cost
Solution Approach 2:
The patent enables the display system to generate its own privacy effect through internal image processing capabilities. The control electronics within the display device itself processes the image data to create the privacy effect, eliminating the need for external or additional optical elements that would otherwise be required to modify view angle properties
3Object-affected harmful factors
If pixel splitting is applied to concentrate luminance, then off-axis luminance difference increases, but on-axis image quality may be disrupted
Solution Approach 1:
The patent applies different luminance concentration strategies to odd and even pixels based on their individual characteristics. By analyzing the specific off-axis to on-axis luminance response of each pixel type and applying customized processing, the system optimizes off-axis luminance difference for each pixel group while maintaining overall on-axis image quality through coordinated processing of adjacent pixels
Solution Approach 2:
The patent incorporates feedback mechanisms where the system analyzes the luminance response characteristics of the display and adjusts the pixel splitting algorithm accordingly. By measuring or characterizing the off-axis to on-axis luminance response and using this information to optimize the image processing parameters, the system achieves maximum privacy effect while minimizing disruption to on-axis image quality
Data Source
AI summary
A display device includes control electronics and a pixellated liquid crystal (LC) panel. The control electronics receives inputs of main image data for a main image and side image data for a side image. The control electronics outputs combined image data combining the main and side images such that an on-axis viewer perceives from the combined image the main image, and an off-axis viewer perceives from the combined image the side image. The output image data comprises data values chosen from a set of available output data values for the pixels selected from multiple sets of available data values depending on at least on the side image data. For a pixel currently being processed, the output data value is chosen from the selected set of available output data values for which a resulting luminance value is closest to a target luminance value for the current pixel.