Transflective LCD Alignment Regulators Overlapping Reflective Film
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transflective liquid crystal display devices face issues with narrow viewing angles and display defects such as afterimages and unevenness due to the use of projections for alignment control, which affect brightness and visual characteristics, especially when viewed from oblique directions.
Innovation Solution
A liquid crystal display device with a multi-gap structure and alignment regulating devices like slit-shaped openings or convex-shaped portions on the electrodes, which overlap with the reflective film, to control liquid crystal alignment and reduce disinclination, allowing for a wide viewing angle and improved brightness by using these areas for both transmissive and reflective displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If projections are provided on the counter substrate to control liquid crystal alignment in transmissive display areas, then alignment control is improved, but display defects such as afterimages and unevenness occur when viewed from oblique directions
Solution Approach 1:
The patent extracts the alignment control function from the counter substrate projections and relocates it to the TFT substrate. By forming convex-shaped portions or slit-shaped opening portions on the TFT substrate, the alignment regulating function is separated from the counter substrate, eliminating the source of display defects while maintaining alignment control capability.
Solution Approach 2:
The patent changes the spatial dimension of alignment control by moving it from the counter substrate side to the TFT substrate side. This dimensional shift allows the alignment regulating portions to overlap with the reflective film in plan view, enabling simultaneous control of both transmissive and reflective display areas without causing oblique viewing defects.
2Reliability
If a transflective plate is provided at the inner surface of the liquid crystal cell to prevent parallax, then reflective display is improved, but the viewing angle in transmissive display becomes narrow
Solution Approach 1:
The patent applies local quality by providing alignment regulating portions only in specific areas that overlap with the reflective film. This localized approach allows different regions of the display to have different optical characteristics, enabling wide viewing angles in transmissive display while maintaining reflective display performance through the reflective film.
Solution Approach 2:
The alignment regulating portions serve multiple functions: they control liquid crystal alignment in transmissive display areas and simultaneously regulate alignment in reflective display areas by overlapping with the reflective film. This multi-functionality allows the same structure to improve both transmissive and reflective display characteristics.
3Ease of manufacture
If the same liquid crystal layer thickness is used in both transmissive and reflective display areas, then manufacturing is simplified, but electro-optical characteristics cannot be optimized for both modes
Solution Approach 1:
The patent applies local quality by creating regions with different liquid crystal layer thicknesses tailored to specific display modes. The transmissive display areas have one thickness optimized for backlight transmission, while the reflective display areas have a different thickness optimized for external light reflection, allowing each region to have optimal electro-optical characteristics.
Solution Approach 2:
The patent segments the liquid crystal layer thickness into different regions corresponding to transmissive and reflective display areas. This segmentation allows independent optimization of thickness for each display mode, with the alignment regulating portions defining the boundaries and characteristics of each segment.
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 effectively reduces display defects and maintains brightness, enabling a wide viewing angle and high display quality by regulating liquid crystal alignment and utilizing the alignment regulating areas for both transmissive and reflective modes, thus enhancing the overall display performance.
Implementation Method 1
a liquid crystal layer is interposed between an upper substrate and a lower substrate... a liquid crystal having a negative dielectric anisotropy whose initial alignment state is vertical, electrodes to drive the liquid crystal are formed on the pair of substrates
Implementation Method 2
a reflective film obtained by forming window portions to transmit light in a metal film made of aluminum, etc., is provided on the inner surface of a lower substrate... the external light incident from the upper substrate side passes through the liquid crystal layer, is reflected from the reflective film
Implementation Method 3
the electrodes of at least one of the substrates are provided with slit-shaped opening portions formed by making opening portions in parts of the electrodes, and/or convex-shaped portions made of a dielectric substance formed on the electrodes, as an alignment regulating device to regulate the alignment of the liquid crystal
Data Source
AI summary
The invention provides a liquid crystal display device in which generation of display defects, such as afterimages or spot-shaped stains, can be reduced or suppressed, and in addition a bright display having a wide viewing angle can be obtained, in a transflective liquid crystal display device. A liquid crystal display device according to the present invention includes a liquid crystal layer interposed between a pair of substrates, and a transmissive display area and a reflective display area provided in one dot area. The liquid crystal layer includes a liquid crystal having a negative dielectric anisotropy representing that an initial alignment state is a vertical alignment, and pixel electrodes to drive the liquid crystal and a common electrode are formed in the liquid crystal layer sides of the pair of substrates, respectively. In the pixel electrodes, as an alignment regulating device to regulate alignment of the liquid crystal, slits formed by opening some parts of the electrodes are formed in the transmissive display areas, and the slits are arranged to two-dimensionally overlap with a reflective film.