Transflective LCD Subpixel Design for Viewing Angle and Visibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transflective liquid crystal display devices face challenges in achieving wide viewing angles and excellent visibility under varying light environments, particularly outdoors, due to differences in voltage-luminance characteristics between transmissive and reflective display regions.
Innovation Solution
The implementation of a transflective liquid crystal display device with a configuration that includes a liquid crystal display panel having subpixels with both transmissive and reflective portions, where the transmissive portion is driven by the IPS system and the reflective portion is driven by a vertical electric field system, utilizing pectinate electrodes and a built-in retarder to optimize liquid crystal layer thickness and orientation for improved visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid crystal layer thickness is reduced in the reflective display region to achieve normally black display, then the reflective display performance is improved, but the voltage-luminance characteristic becomes different from the transmissive display region
Solution Approach 1:
The patent applies different liquid crystal layer thicknesses to different regions: the transmissive display region has a standard thickness (d1) while the reflective display region has a reduced thickness (d2). This local differentiation allows the reflective region to achieve normally black display while the transmissive region maintains its characteristic voltage-luminance response.
Solution Approach 2:
The patent changes the physical parameter of liquid crystal layer thickness to resolve the contradiction. By setting d2 < d1 (specifically d2 is about half of d1), the reflective region achieves the desired normally black state without affecting the transmissive region's voltage-luminance characteristics.
2Adaptability or versatility
If the transmissive display region is driven by IPS system and reflective display region by vertical electric field system, then wide viewing angle and outdoor visibility are achieved, but the device structure becomes complex
Solution Approach 1:
The display panel is segmented into two distinct drive system regions: the transmissive display region uses the IPS system with pixel electrodes and common electrodes forming a planar electric field, while the reflective display region uses the vertical electric field system with pixel electrodes and counter-electrodes forming a vertical electric field. This segmentation allows each region to be optimized for its specific function.
Solution Approach 2:
The liquid crystal layer serves multiple functions simultaneously: it enables both IPS-mode transmissive display and vertical-field reflective display within the same layer structure. The pixel electrodes and common electrodes are configured to provide both planar and vertical electric field components as needed.
3Adaptability or versatility
If different drive systems are used for transmissive and reflective regions, then transmissive display at wide viewing angle and excellent outdoor visibility are enabled, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality by creating distinct thickness zones: the transmissive region maintains a standard thickness d1 while the reflective region has a reduced thickness d2. This is achieved through selective formation of the liquid crystal layer or selective removal of a spacer layer in the reflective region.
Solution Approach 2:
The different thickness configuration is built into the device structure during manufacturing before operation. The liquid crystal layer thickness is pre-determined in each region through the spacer layer configuration or formation process, eliminating the need for post-manufacturing adjustment.
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 enables transmissive display at wide viewing angles and maintains excellent visibility even in bright outdoor environments by balancing the voltage-luminance characteristics and reflectivity across both display regions.
Implementation Method 1
liquid crystal is rotated within a substrate plane to conduct light and dark control
Implementation Method 2
an electric field is applied between the pixel electrodes and the common electrode
Implementation Method 3
a retarder formed between the second common electrodes and the second substrate
Data Source
AI summary
A transflective liquid crystal display device includes a liquid crystal display panel having a first substrate, a second substrate, and a liquid crystal interposed between the first substrate and the second substrate in which the liquid crystal display panel includes a plurality of subpixels having a transmissive portion and a reflective portion, wherein the transmissive portion of each of the plurality of subpixels includes a first common electrode formed on the first substrate, and a transmissive pixel electrode formed on the first common electrode through an interlayer insulating film, wherein the transmissive pixel electrode has a plurality of pectinate electrodes or slits, and wherein the reflective portion of each of the plurality of subpixels includes a reflective electrode formed on the first common electrode, a planar reflective pixel electrode formed on the first common electrode through the interlayer insulating film, second common electrodes formed on the second substrate, and a retarder formed between the second common electrodes and the second substrate.