Diffractive Optical Element for LCD Viewing Angle Uniformity
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Solution Overview
Problem
Conventional wide viewing angle liquid crystal display devices suffer from significant differences in image color and brightness at various observation angles, leading to image deviation and decreased contrast due to light leakage.
Innovation Solution
A display apparatus comprising a liquid crystal display device, a first polarizer, a second polarizer, and a diffractive optical element, where the liquid crystal panel has a pretilt angle of at least 60 degrees and the diffractive optical element with a diffraction grating is positioned on the light emitting side of the first polarizer, optimizing the polarizing directions and diffraction grating angles to improve viewing angle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional wide viewing angle liquid crystal display device is used, then the viewing angle is wide, but the image color and brightness differ significantly at different observation angles
Solution Approach 1:
The invention divides the liquid crystal display into multiple domains with different liquid crystal tilt directions. Each domain is oriented to control light transmission in specific viewing directions, thereby segmenting the viewing space to achieve uniform image quality across different observation angles while maintaining a wide overall viewing angle
Solution Approach 2:
The invention changes the physical parameters of the liquid crystal molecules by applying electrical fields to control their tilt angles and orientations. By adjusting the liquid crystal tilt direction in different domains through voltage control, the display achieves consistent image brightness and color across various viewing angles
2Adaptability or versatility
If the viewing angle is increased, then the observation range is wider, but the image deviation problem becomes more serious
Solution Approach 1:
The display is divided into multiple domains with specific tilt directions (e.g., ±20°, ±40°) to control image positioning in different viewing zones. This segmentation ensures that even at wide viewing angles, the image remains properly positioned by directing light appropriately in each domain
Solution Approach 2:
The invention employs asymmetric domain configurations with different tilt angles in different regions of the display. This asymmetric arrangement of liquid crystal domains compensates for image deviation at various viewing angles, maintaining accurate image positioning across the entire viewing cone
3Adaptability or versatility
If the viewing angle is increased, then the observation range is wider, but the contrast decreases due to light leakage
Solution Approach 1:
By segmenting the liquid crystal layer into multiple domains with different tilt directions, the invention controls light transmission paths in each domain. This prevents unwanted light leakage from adjacent domains, thereby maintaining high contrast ratios even when viewed from wide angles
Solution Approach 2:
The invention introduces alignment films and specific liquid crystal materials as intermediaries that control molecular orientation and light transmission. These intermediary layers ensure that light passes through only the intended domains at each viewing angle, preventing cross-domain light leakage and maintaining contrast
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 image quality by minimizing color and brightness variations across different viewing angles, maintaining high contrast and reducing light leakage, thereby improving the overall display performance.
Implementation Method 1
the diffractive optical element comprises a first diffraction grating and is disposed on a light emitting side of the first polarizer
Implementation Method 2
As an electrical field is applied in the liquid crystal layer, the liquid crystal molecules are tilted into a liquid crystal tilt direction by the electrical field
Implementation Method 3
The first polarizer has a light absorbing axis
Data Source
AI summary
A display apparatus and a polarizer for multi-domain vertical aligned liquid crystal display apparatus are provided. The display apparatus includes a liquid crystal display device, a first polarizer, a second polarizer and a diffractive optical element. The first polarizer is disposed on the first substrate. The second polarizer is disposed between the second substrate and the backlight module. The diffractive optical element includes a first diffraction grating and is disposed on a light emitting side of the first polarizer. An azimuth angle the first diffraction grating is counted from an absorbing axis of the first polarizer as standard.