Display Panel Gray Scale Expression Using Segmented Electrodes
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Solution Overview
Problem
Liquid crystal display panels using the spatial division scheme to express multiple gray scales require a large number of transistors, leading to increased pixel area and degraded resolution.
Innovation Solution
A display panel design with a reduced number of transistors that uses a combination of data lines, gate lines, switching devices, and coupling capacitors to achieve multiple gray scales without degrading resolution, by employing a cholesteric or bistable liquid crystal layer that undergoes phase transitions based on voltage, allowing for efficient gray scale expression through the use of multiple pixel electrodes and capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the spatial division scheme is adopted to express multiple gray scales, then the number of expressed gray scales increases, but the pixel area is enlarged and resolution is degraded
Solution Approach 1:
The pixel electrode is divided into multiple portions (first portion, second portion, third portion) with different liquid crystal layer thicknesses, allowing each portion to express different gray scales independently. This segmentation enables multiple gray scale expression without increasing the overall pixel area, as the gray scale differentiation is achieved through internal structural division rather than adding more transistors or expanding pixel dimensions.
Solution Approach 2:
Instead of using the conventional approach of adding more transistors in the planar dimension to increase gray scale expression capability, this invention introduces a vertical dimension by varying the liquid crystal layer thickness between the pixel electrode portions and the common electrode. This dimensional transition from 2D planar division to 3D vertical differentiation allows multiple gray scales to be expressed within the same pixel footprint.
2Adaptability or versatility
If the spatial division scheme is adopted to express multiple gray scales, then the number of expressed gray scales increases, but the resolution is degraded
Solution Approach 1:
The pixel electrode is segmented into multiple portions with different liquid crystal layer thicknesses, enabling each portion to contribute to different gray scale levels. This segmentation approach increases the information capacity within each pixel without requiring additional transistors that would reduce the active display area and degrade resolution.
Solution Approach 2:
The invention changes the physical parameter of liquid crystal layer thickness to differentiate gray scales. By controlling the thickness of the liquid crystal layer between different portions of the pixel electrode and the common electrode, multiple gray scale levels are achieved through parameter variation rather than through increased transistor count, thereby maintaining high resolution.
3Adaptability or versatility
If multiple pixel electrodes and coupling capacitors are used to express multiple gray scales, then the gray scale expression capability increases, but the device complexity increases
Solution Approach 1:
The invention merges the functions of multiple pixel electrodes and coupling capacitors into a single pixel electrode structure with multiple portions. Instead of using separate electrodes and capacitors for each gray scale level, the different portions of the pixel electrode with varying liquid crystal layer thicknesses collectively perform the gray scale expression function, thereby reducing device complexity while maintaining gray scale capability.
Solution Approach 2:
The pixel electrode is designed to serve multiple functions simultaneously - each portion of the pixel electrode not only defines a specific gray scale level but also acts as both an electrode and a thickness control element. This multi-functionality eliminates the need for separate coupling capacitors and multiple pixel electrodes, reducing overall device complexity while maintaining the ability to express multiple gray scales.
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 enables the display panel to express multiple gray scales with a reduced number of transistors, maintaining high resolution by utilizing the phase transition properties of cholesteric or bistable liquid crystals and optimizing the configuration of pixel electrodes and capacitors.
Implementation Method 1
a liquid crystal layer interposed between the first substrate and the second substrate and subject to a phase transition depending on a voltage generated in relation to the gray scale expression unit
Implementation Method 2
employing a cholesteric or bistable liquid crystal layer that undergoes phase transitions based on voltage
Implementation Method 3
at least one coupling capacitor connected to the first pixel electrode in parallel
Data Source
AI summary
A display panel includes a first substrate, a second substrate facing the first substrate, and a liquid crystal layer. The first substrate includes a plurality of pixels, each having at least one gray scale expression unit to express at least two gray scales. The liquid crystal layer is interposed between the first and second substrates and subject to a phase transition depending on a voltage generated in relation to the gray scale expression unit. The gray scale expression unit includes a data line, a gate line crossing the data line and insulated from the data line, a switching device connected to the data line and the gate line, a first pixel electrode connected to the switching device, at least one coupling capacitor connected to the first pixel electrode in parallel, and at least one second pixel electrode connected to the first pixel electrode in parallel through the coupling capacitor.