Semi-Transparent LCD Viewing Angle Symmetry via Dielectric Protrusions
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Solution Overview
Problem
Semi-transparent LCD devices exhibit asymmetry in vertical or horizontal visual field angle characteristics, leading to color tone deviation, which affects the quality of image display.
Innovation Solution
The implementation of a semi-transparent LCD device with a transmission and reflection part in each pixel, featuring first and second linear dielectric protrusions that align liquid crystal molecules at right angles, along with a specific optical film configuration, including polarizers and retardation plates, to achieve parallel alignment and control tilt angles, ensuring symmetry in viewing angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If homogeneous alignment scheme using liquid crystal material with positive permittivity anisotropy is used, then response time is improved, but asymmetry in visual field angle characteristics occurs causing color tone deviation
Solution Approach 1:
The pixel is divided into multiple domains (first domain and second domain) with different liquid crystal alignment directions. The first domain has liquid crystal molecules aligned in a first direction while the second domain has molecules aligned in a second direction different from the first direction. This segmentation allows each domain to contribute differently to the overall optical characteristics, achieving symmetry in visual field angle characteristics while maintaining fast response time of homogeneous alignment
Solution Approach 2:
Within each domain, asymmetric alignment configurations are employed where liquid crystal molecules are tilted at specific angles (first tilt angle in first domain, second tilt angle in second domain) relative to the substrate normal. These asymmetric domain-level configurations are designed to cancel out when viewed from different angles, resulting in symmetric overall visual field characteristics
2Manufacturing precision
If multi-domain alignment is implemented to symmetrize visual field angle characteristics, then color tone deviation is reduced, but device structure becomes more complex
Solution Approach 1:
Different regions (domains) within the pixel are assigned different alignment qualities - specifically, different tilt angles and alignment directions are applied locally in each domain. The first domain has liquid crystal molecules tilted at a first angle in a first direction, while the second domain has molecules tilted at a second angle in a second direction. This local differentiation achieves symmetric visual field characteristics without requiring complex external control mechanisms
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 results in high contrast ratio, high display efficiency, and improved symmetry in vertical and horizontal viewing angle characteristics, enhancing visual recognition in information terminal devices like portable telephones.
Implementation Method 1
a first linear dielectric protrusion disposed between the common electrode and the liquid crystal layer so as to extend over a plurality of pixels in a short side direction of pixels, the first linear dielectric protrusion being disposed nearly in center of the transmission part, and a second linear dielectric protrusion disposed in the reflection part between the common electrode and the first substrate
Implementation Method 2
a liquid crystal layer is interposed between a pair of substrates (hereafter also referred to as 'first substrate and second substrate') and an electronic latent image is converted to a visible image by controlling the molecular alignment of liquid crystal composites included in the liquid crystal layer by means of an electric field applied to the liquid crystal layer
Implementation Method 3
a first sheet polarizer, a first A-plate and a first negative C-plate provided between a back light used as a light source and a LCD cell
Implementation Method 4
a first A-plate and a first negative C-plate provided between a back light used as a light source and a LCD cell
Implementation Method 5
an image is displayed by using light incident from the observation side. In the semi-transparent type LCD devices, transmitted light obtained from light incident from a side opposite to an observation side and/or light incident from the observation side can be used simultaneously or selectively to display an image
Data Source
AI summary
A semi-transparent homogeneous-alignment LCD device including a transmission part and a reflection part, a first linear dielectric protrusion disposed between a common electrode and a liquid crystal layer so as to extend over a plurality of pixels in a short side direction of pixels and be disposed nearly in center of the transmission part, anda second linear dielectric protrusion disposed in the reflection part between the common electrode and a first substrate so as to extend over a plurality of pixels in the short side direction, wherein an alignment direction of liquid crystal molecules crosses the first and second linear dielectric protrusions at right angles and is parallel to a long side direction of pixels, and a tilt angle of the liquid crystal molecules is approximately 0°, or even if there is a pre-tilt angle, the tilt angle of the liquid crystal molecules is 2° or less.