Transflective LCD Common Electrode Slits for Contrast and Viewing Angle
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Solution Overview
Problem
In liquid crystal display devices without circular polarizers, the contrast ratio is compromised due to the quarter-wave plate and the alignment of liquid crystal molecules, which also affects brightness and viewing angle.
Innovation Solution
The design incorporates a common electrode with slits or protrusions that overlap data lines, and a pixel electrode with slits or protrusions, where the data lines and reflective layer overlap these features, to control liquid crystal molecule alignment and enhance contrast ratio and viewing angle without contributing to brightness loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If circular polarizers are used in VA system liquid crystal display devices, then the contrast ratio can be improved, but the manufacturing precision and consistency become difficult to maintain due to quarter-wave plate retardation variations and alignment issues
Solution Approach 1:
The patent removes the circular polarizer (quarter-wave plate) from the display structure entirely. By using a VA system with linear polarizers and controlling liquid crystal molecule alignment through electrode slits/protrusions, the device achieves high contrast ratio without requiring the problematic circular polarizer component, thus eliminating the manufacturing precision issues associated with it
Solution Approach 2:
The patent introduces slits or protrusions in the electrode structures to create localized alignment regions. These local structural modifications guide liquid crystal molecule orientation in specific areas without affecting the entire display structure, enabling precise control of light transmission and reflection properties while maintaining manufacturing feasibility
2Measurement precision
If liquid crystal molecules are aligned for high contrast ratio, then the contrast ratio improves, but the viewing angle becomes limited
Solution Approach 1:
The patent employs a transflective display structure that utilizes both transmission and reflection modes. By incorporating a reflective layer and controlling liquid crystal alignment to work with both transmitted and reflected light paths, the device achieves high contrast ratio in the vertical direction while expanding the effective viewing angle through the reflective component that captures light from multiple angles
3Measurement precision
If slits and protrusions are added to control liquid crystal alignment, then the contrast ratio and viewing angle improve, but the device complexity increases
Solution Approach 1:
The patent combines the alignment control function into the existing electrode structures by adding slits or protrusions to the common electrode and/or pixel electrode. Rather than introducing separate alignment layers or additional components, the alignment control is integrated directly into the electrode pattern design, simplifying the overall device structure while achieving the desired liquid crystal orientation
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 achieves a bright liquid crystal display with a high contrast ratio and wide viewing angle by optimizing the alignment of liquid crystal molecules and reducing the impact of slits and protrusions on transmissive displays.
Implementation Method 1
the state of polarization of light that enters into the liquid crystal layer is changed so that an image is displayed
Implementation Method 2
a liquid crystal layer sandwiched between these transparent substrates
Implementation Method 3
a polarizer which functions to absorb a predetermined linearly polarized light component and allows linearly polarized light perpendicular to this component to transmit
Implementation Method 4
reflective displays are gained by controlling the amount of reflected light from the outside in the reflection area
Data Source
AI summary
An object of the present invention is to implement a bright liquid crystal display device having a high contrast ratio and a wide viewing angle. A liquid crystal display device according to the present invention has: a number of data lines; gate lines formed so as to cross the number of data lines; a number of switching elements formed in locations where the number of data lines and the number of gate lines cross; a reflection area and a transmission area formed within each pixel; a liquid crystal layer sandwiched between first and second substrates; a common electrode placed between the first substrate and the liquid crystal layer; and a pixel electrode placed between the second substrate and the liquid crystal layer, and the common electrode has slits or protrusions, and the data lines overlap the slits in the common electrode or protrusions of the common electrode in the direction of normal to a surface of the first substrate in the configuration.