Liquid Crystal Display Common Electrode Slit Design for Light Leakage Control
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Solution Overview
Problem
In high-definition liquid crystal display devices, the narrow width of the light-shielding layer opposite to line portions leads to light leakage near these areas, reducing the contrast ratio and potentially decreasing the aperture ratio of pixels, especially as pixel size decreases.
Innovation Solution
The configuration includes a common electrode with slits extending in a direction different from the gate and data lines, which are bent and positioned to oppose both the pixel electrodes and the line portions, maintaining the plane of vibration of polarized light and reducing reflections, thereby minimizing light leakage without increasing the light-shielding layer width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the width of the light-shielding layer is increased to suppress light leakage near the line portions, then light leakage is reduced, but the aperture ratio of pixels is reduced
Solution Approach 1:
A light-shielding film is introduced as an intermediary element positioned between the line portions and the pixel electrodes. This film has a specific refractive index that differs from both the resin layer and the liquid crystal layer, creating optical impedance matching that reduces light leakage at the boundaries without requiring an increase in the light-shielding layer width. The light-shielding film acts as a transition medium that manages light reflection and refraction at the interfaces.
Solution Approach 2:
The invention changes the optical parameters of the structure by introducing a light-shielding film with a specific refractive index range (1.4-1.6) that is intermediate between the resin layer (refractive index ~1.5) and the liquid crystal layer. This parameter adjustment optimizes light reflection and refraction at the boundaries, suppressing light leakage without increasing the light-shielding layer width, thereby maintaining the aperture ratio.
2Measurement precision
If the pixel size is reduced to achieve high definition, then display resolution is improved, but the width of the light-shielding layer becomes narrower leading to increased light leakage
Solution Approach 1:
The light-shielding film serves as a mediator that becomes particularly effective when pixel sizes are reduced. As pixels become smaller, the light-shielding layer width necessarily decreases, making the intermediary light-shielding film crucial for maintaining optical performance. The film compensates for the reduced width by optimizing light reflection and refraction at the boundaries through its specific refractive index.
Solution Approach 2:
By adjusting the refractive index parameter of the light-shielding film to be intermediate between the resin and liquid crystal layers, the invention enables high-definition displays with smaller pixels while suppressing light leakage. This parameter optimization allows the system to achieve high resolution without sacrificing contrast ratio due to light leakage.
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 display quality by maintaining the plane of vibration of polarized light, suppressing light leakage, and preventing a reduction in contrast ratio, while allowing for a wider viewing angle and expanded opening portions without increasing the light-shielding layer width.
Implementation Method 1
liquid crystal molecules initially aligned in the second direction
Implementation Method 2
a first polarizer disposed on a side opposite to a side of the first substrate, which is opposed to the second substrate, and having a first transmission axis perpendicular or parallel to the second line
Implementation Method 3
a second polarizer disposed on a side opposite to a side of the second substrate, which is opposed to the first substrate, and having a second transmission axis orthogonal to the first transmission axis
Implementation Method 4
maintaining the plane of vibration of polarized light and reducing reflections
Data Source
AI summary
According to one embodiment, a liquid crystal display device, includes a first substrate including a second line extending in a second direction, a first interlayer insulating film, a first electrode, a second interlayer insulating film, and a second electrode, a second substrate, a liquid crystal layer containing liquid crystal molecules initially aligned in the second direction, a first polarizer having a first transmission axis perpendicular or parallel to the second line, and a second polarizer having a second transmission axis orthogonal to the first transmission axis.