Transflective LCD Panel Single Cell Gap Design
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Solution Overview
Problem
Conventional transflective TFT-LCD panels with a single cell gap face challenges in achieving optimal opto-electrical performance due to differing light paths through transmissive and reflective regions, leading to unfavorable display performance and increased complexity in manufacturing.
Innovation Solution
A liquid crystal display (LCD) panel design with a single cell gap, utilizing an active array substrate with specific scan lines, data lines, and active devices to control pixel voltages, allowing for equal light paths through transmissive and reflective regions, thereby eliminating differences in optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single cell gap is used in transflective TFT-LCD panels, then the manufacturing complexity is reduced, but the opto-electrical performance becomes unfavorable due to different light path lengths in transmissive and reflective regions
Solution Approach 1:
The patent applies local quality by creating different cell gap structures in different regions: the transmissive region has a first cell gap while the reflective region has a second cell gap that is different from the first. This allows each region to be optimized for its specific optical function, with the transmissive region optimized for backlight transmission and the reflective region optimized for front-light reflection, thereby achieving favorable opto-electrical performance while maintaining a single cell gap overall structure
Solution Approach 2:
The patent segments the cell gap into two distinct parts: a first cell gap in the transmissive region and a second cell gap in the reflective region. This segmentation allows independent optimization of each region's optical path length, enabling the light path in the reflective region to be equalized with the transmissive region's optical path, thus resolving the opto-electrical performance issue while maintaining manufacturing simplicity
2Manufacturing precision
If different cell gaps are used in transmissive and reflective regions, then equal light paths are achieved, but the device complexity increases
Solution Approach 1:
The patent merges the transmissive and reflective regions into a single cell gap structure where the first and second cell gaps are integrated within one continuous cell gap. This merging approach allows different local cell gap dimensions while maintaining overall structural unity, avoiding the need for completely separate cell gap systems and thereby reducing device complexity compared to dual cell gap designs
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 design enables the same gray level to be displayed in both transmissive and reflective regions, simplifying the fabrication of the transflective LCD panel and reducing manufacturing costs while maintaining improved display performance.
Implementation Method 1
When same voltages are respectively applied to liquid crystal molecules in the transmissive region 104a and in the reflective region 102a, the light beams should have a phase retardation of half the wavelength after passing through the transmissive region 104a
Implementation Method 2
the light beams should have a phase retardation of half the wavelength after passing through the transmissive region 104a, and should have a phase retardation of one quarter of the wavelength of light after passing through the reflective region 102a
Implementation Method 3
the metal pixel electrode 110a in the reflective region 102a reflects the front-light source or the external light source, while the transparent pixel electrode 120a in the transmissive region 104a allows the light projected by a backlight module
Data Source
AI summary
In a liquid crystal display panel, each pixel unit includes first and second pixels, a first scan line coupled to the first pixel, and a second scan line coupled to the second pixel via an active element. During a first scan period, the first scan line, the second scan line and the active element are all activated to write a first voltage to the first and second pixels. During a second scan period, the first scan line remains activated but the second scan line and the active element are deactivated so that a second voltage is written to the first sub-pixel and the second sub-pixel is maintained at the first voltage.