Quasi-isotropic Liquid Crystal Transflective Display
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Solution Overview
Problem
Semi-transmissive reflective liquid crystal displays face issues with inefficient light reflection on inclined planes, optical path length changes, decreased contrast, and narrow viewing angles due to resin layers, which affect reliability and optical properties.
Innovation Solution
A transflective liquid crystal display using a quasi-isotropic liquid crystal material with optically isotropic and anisotropic properties based on electric field intensity, featuring different electrode distances in transparent and reflective areas to control phase shifts and electric field dimensions, ensuring flat substrates and efficient light usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a resin layer is placed to adjust liquid crystal layer thickness, then the optical path length can be equalized between reflective and transparent areas, but light reflection efficiency decreases and contrast is lowered
Solution Approach 1:
The patent removes the resin layer from the reflective display area, allowing the liquid crystal layer thickness to be naturally uniform across both reflective and transparent areas. This eliminates the inclined plane problem while maintaining adequate optical path length difference through electrode distance adjustment alone.
Solution Approach 2:
The patent replaces the mechanical thickness adjustment method (resin layer) with an electrical field-based control method (different electrode distances). By setting different electrode distances in reflective vs. transparent areas, the optical path length difference is achieved through the liquid crystal material's response to electric fields rather than physical thickness variation.
2Manufacturing precision
If a resin layer is placed to adjust liquid crystal layer thickness, then the optical path length can be equalized between reflective and transparent areas, but the viewing angle becomes narrow
Solution Approach 1:
The patent removes the resin layer that caused the inclined plane, thereby eliminating the viewing angle limitation. The flat substrate structure allows light to enter and exit the liquid crystal layer at various angles without distortion, achieving wide viewing angle performance.
Solution Approach 2:
The patent applies different electrode distances in different areas (reflective vs. transparent) to achieve area-specific optical path control. This local differentiation allows the reflective area to maintain optimal thickness for wide viewing angle while the transparent area achieves adequate optical path length for proper display function.
3Reliability
If different electrode distances are used in transparent and reflective areas, then phase shifts and electric field dimensions can be controlled, but the device structure becomes more complex
Solution Approach 1:
The patent implements different electrode distances in different areas (reflective vs. transparent) to achieve area-specific optical path control. This local differentiation allows the reflective area to maintain optimal thickness for wide viewing angle while the transparent area achieves adequate optical path length for proper display function.
Solution Approach 2:
The electrode structure serves multiple functions: it controls the liquid crystal molecules through electric fields, adjusts optical path length, and enables both reflective and transparent display modes. By making the electrodes multi-functional, the patent avoids adding separate components for each function, thereby limiting the increase in device complexity.
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 configuration enhances visibility in both bright and dark environments with a wide viewing angle, improves light use efficiency, and increases the reliability and durability of the display.
Implementation Method 1
a liquid crystal layer composed of a quasi-isotropic liquid crystal material which is optically isotropic when a non-selected electric field is applied and is optically anisotropic when a selected electric field is applied
Implementation Method 2
the flexibility of which changing according to the electric field intensity
Implementation Method 3
The phase contrast layer 200 gives a phase shift of about 100 to 200 nm to the incident visible light transmitted to the liquid crystal cell 110, working as a quarter wavelength plate to the visible light
Implementation Method 4
A semi-transmissive reflecting layer 180 having a metal film with a high reflectance is formed on the inner surface side of the lower substrate 130
Implementation Method 5
for transmitting the light emitted from the backlight 120
Data Source
AI summary
A transflective liquid crystal display that includes a liquid crystal layer interposed between a pair of substrates facing each other and a transparent display area for transparent display and a reflecting display area for reflecting display within a single pixel area, wherein the liquid crystal layer is composed of a quasi-isotropic liquid crystal material that is optically isotropic when non-selected electric field is applied and is optically anisotropic when selected electric field is applied, the flexibility of which changing according to the electric field intensity, and the electric field intensity is supposed to be set smaller in the reflecting display area than in the transparent display area.