Stacked Liquid Crystal Display Panels for High Contrast Ratio
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Solution Overview
Problem
Liquid crystal display devices face issues with luminance deterioration and color changes when viewed from different angles due to parallax and varying light transmission through stacked panels, leading to suboptimal contrast ratios and display quality.
Innovation Solution
A liquid crystal display device structure that stacks a single first liquid crystal display element with a color filter and one or more second elements without a color filter, using an image processing unit to generate drive signals based on maximum relative gradations or transmittances, ensuring consistent image display across viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple liquid crystal display panels are stacked to improve contrast ratio, then contrast ratio is improved, but luminance deterioration and color changes occur when viewed from different angles
Solution Approach 1:
The display system is divided into multiple independent liquid crystal display panels (first display panel with color filter, second display panel without color filter) stacked in the optical axis direction. Each panel operates independently with its own drive signals, allowing the system to achieve high contrast ratio while managing luminance and color characteristics through coordinated control of separate panels.
Solution Approach 2:
Different liquid crystal display panels are assigned different characteristics: the first panel includes a color filter layer for color display, while the second panel omits the color filter layer for improved luminance and contrast. This local differentiation allows each panel to optimize for specific functions, with the color filter panel providing color information and the non-color-filter panel providing high-contrast luminance control.
2Manufacturing precision
If multiple liquid crystal display panels are stacked to improve contrast ratio, then contrast ratio is improved, but parallax occurs causing position shift between panels when viewed from different angles
Solution Approach 1:
The system performs preliminary image processing to generate different drive signals for each liquid crystal display panel before display. The image processing unit creates panel-specific signals that compensate for potential parallax effects, ensuring that even when panels are viewed from angled positions, the displayed content remains properly aligned and free from position shifts.
Solution Approach 2:
The control unit coordinates the drive signals of multiple liquid crystal display panels based on feedback from the image processing unit. By adjusting the timing and intensity of drive signals for each panel, the system compensates for parallax-induced position shifts, maintaining proper alignment across all panels regardless of viewing angle.
3Manufacturing precision
If multiple liquid crystal display panels are stacked to improve contrast ratio, then contrast ratio is improved, but color changes occur due to varying light transmission through different panels
Solution Approach 1:
The display system segments color and luminance functions across different panels: the first liquid crystal display panel with color filter handles color information, while the second panel without color filter handles luminance control. This segmentation allows independent optimization of color and luminance characteristics, preventing color shifts that would occur if both panels had identical color filter structures.
Solution Approach 2:
The system changes the optical parameters of different panels by selectively including or excluding color filter layers. The first panel has color filter layers with specific transmission characteristics, while the second panel lacks these layers to provide different (more neutral) transmission characteristics. This parameter differentiation enables the system to maintain color consistency across panels while achieving high contrast ratio.
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 enhances contrast ratios and maintains display quality by minimizing luminance and chromaticity changes when viewed from different angles, achieving a high contrast ratio of 500,000:1 while preventing luminance deterioration and color shifts.
Implementation Method 1
TN-type liquid crystal layers 931, 932 interposed between the pair of transparent substrates
Implementation Method 2
polarization plates 901, 902, 903, 904 disposed on both sides of the pair of transparent substrates
Data Source
AI summary
To provide a liquid crystal display device and the like, which can improve the contrast ratio. The liquid crystal display device includes a liquid crystal display unit and an image processing unit which supplies video signals inputted from a video source section to the liquid crystal display unit. The liquid crystal display unit is formed by stacking a single first liquid crystal display element and a single or a plurality of second liquid crystal display element(s). For each pixel unit of the second liquid crystal display element, the image processing unit generates, by having each dot of the video signal as a reference point, a drive signal for displaying an image according to processing for extracting a maximum value of relative gradations or relative transmittances among a region of a pixel unit (dot) group including the reference pixel units and the pixel units (dots) neighboring to the reference pixel units.