Transflective Display Module Polarization Optimization
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Solution Overview
Problem
Existing transflective liquid crystal display modules suffer from low brightness, low contrast, color shift, and other issues due to dispersion effects across different wave bands in visible light.
Innovation Solution
A display module design that includes a first and second substrate with a liquid crystal layer, along with specific configurations of polarizing films, one-half wave plates, and quarter wave plates, optimized for transmissive and reflective regions to improve polarization conversion efficiency and reduce light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional transflective liquid crystal display modules are used, then the display can function in both transmissive and reflective modes, but the brightness and contrast are low due to dispersion effects across different wave bands
Solution Approach 1:
The display module is divided into distinct transmissive and reflective regions on the substrate, with each region having optimized optical path configurations. The transmissive region includes a backlight unit and specific polarizing film arrangement, while the reflective region uses a reflection layer and different polarizing configuration, allowing independent optimization of each mode to improve brightness without excessive overall complexity
Solution Approach 2:
Different regions of the display module are given different optical properties and structures tailored to their specific functions. The transmissive region uses a first polarizing film with specific orientation while the reflective region uses a second polarizing film with different orientation, and the liquid crystal layer has different thickness or orientation in different regions to optimize local optical performance for each mode
Solution Approach 3:
The display module employs composite optical structures combining multiple functional layers including polarizing films, quarter-wave plates, half-wave plates, liquid crystal layers, and reflection layers. These composite structures work together to manage light polarization and reflection differently in transmissive versus reflective regions, improving overall brightness and contrast while managing the complexity through integrated design
2Adaptability or versatility
If conventional transflective liquid crystal display modules are used, then the display can operate in outdoor and indoor modes, but color shift occurs due to dispersion effects across different wave bands
Solution Approach 1:
The display is segmented into transmissive and reflective regions with independently optimized optical paths. The transmissive region is optimized for indoor viewing with backlight illumination, while the reflective region is optimized for outdoor viewing with ambient light reflection, allowing each region to maintain color accuracy in its intended environment without the other mode's dispersion effects interfering
Solution Approach 2:
Different regions use locally optimized polarizing film orientations and liquid crystal configurations tailored to their specific viewing conditions. The transmissive region uses a first polarizing film orientation optimized for backlight transmission, while the reflective region uses a second polarizing film orientation optimized for ambient light reflection, ensuring color accuracy in each local environment
Solution Approach 3:
The optical parameters such as polarizing film orientation angles, liquid crystal layer thickness, and wave plate retardation are specifically adjusted for different regions to compensate for dispersion effects. By changing these parameters locally in transmissive versus reflective regions, the display maintains color accuracy across different operating modes despite the inherent dispersion in liquid crystal materials
3Illumination intensity
If conventional transflective liquid crystal display modules are used, then the display can provide both transmissive and reflective functionality, but light leakage reduces contrast
Solution Approach 1:
The patent extracts and separates the light management functions into distinct components: polarizing films are used to extract and control polarization states, quarter-wave and half-wave plates are used to convert between linear and circular polarization, and reflection layers are used to extract and redirect light. This separation allows precise control of light paths to minimize leakage and improve contrast
Solution Approach 2:
Wave plates (quarter-wave and half-wave plates) serve as intermediary elements that convert between different polarization states. These intermediaries enable precise control of light transmission and reflection by converting linearly polarized light to circularly polarized light and back, allowing the display to achieve high contrast by controlling which polarization states are transmitted or reflected in each region
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 proposed solution enhances the light effect of reflection and transmission, achieving high brightness and contrast by reducing dispersion effects and improving linear-circular polarization conversion efficiency.
Implementation Method 1
the liquid crystal layer adopts an electrically controlled birefringence type liquid crystal
Implementation Method 2
improving linear-circular polarization conversion efficiency
Implementation Method 3
the reflective region allows light incident from a side of the second substrate away from the first substrate to be reflected
Data Source
AI summary
A display module, including: a first substrate (1); a second substrate (2); a liquid crystal layer (3); the display module further includes a first polarizing film (4), a first one-half wave plate (51) and a first quarter wave plate (52); the first quarter wave plate (52), the first one-half wave plate (51) and the first polarizing film (4) are on a side of the first substrate (1) away from the liquid crystal layer (3) and are sequentially stacked in a direction away from the first substrate (1); an angle between an absorption axis of the first polarizing film (4) and a first direction is in a range of 85° to 105°; an angle between a slow axis of the first one-half wave plate (51) and the first direction is in a range of 105° to 125°.