Hybrid Guest Host Liquid Crystal Display Panel for Brightness and Contrast
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Solution Overview
Problem
Reflective-type display panels suffer from low brightness and low contrast due to limited light utilization, making them unsuitable for high-demand applications.
Innovation Solution
A display panel comprising an optical component with a cholesteric liquid crystal layer and two Guest Host liquid crystal cells, each with pixel units that can switch between natural light and linearly polarized light transmission states, allowing for improved light utilization and contrast through the use of ¼ wave plates for polarization conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflective-type display panel is used to achieve low power consumption, then energy efficiency is improved, but brightness and contrast become insufficient
Solution Approach 1:
The patent combines reflective-type and transmissive-type display structures into a single integrated panel. The display panel includes a first substrate, a cholesteric liquid crystal layer, a second substrate, and a polarizer arranged in sequence, creating a hybrid structure that can operate in both reflective and transmissive modes to simultaneously achieve low power consumption and high brightness
Solution Approach 2:
The display panel is designed to function in multiple modes: it can operate as a reflective display using ambient light for ultra-low power consumption, or switch to transmissive mode using a backlight source for high brightness applications, making it universally applicable to various usage scenarios with different lighting conditions
2Use of energy by moving object
If a reflective-type display panel is used to achieve low power consumption, then energy efficiency is improved, but contrast ratio deteriorates
Solution Approach 1:
The patent combines reflective-type and transmissive-type display structures into a single integrated panel. The display panel includes a first substrate, a cholesteric liquid crystal layer, a second substrate, and a polarizer arranged in sequence, creating a hybrid structure that can operate in both reflective and transmissive modes to simultaneously achieve low power consumption and high contrast ratio
Solution Approach 2:
The patent uses a composite structure combining cholesteric liquid crystal material with conventional liquid crystal layers and polarizers. The cholesteric liquid crystal layer provides selective reflection for the reflective mode, while the combination with polarizers enables high contrast ratio in both reflective and transmissive modes
3Illumination intensity
If an optical component is added to improve light utilization, then brightness is improved, but device complexity increases
Solution Approach 1:
The cholesteric liquid crystal layer serves multiple functions: it acts as a reflective element for ambient light, a wavelength-selective filter, and works in conjunction with the polarizer to enable both reflective and transmissive display modes, reducing the need for separate optical components
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
Enhances display brightness and contrast by optimizing light usage without the need for polarizers, reducing manufacturing costs and enabling energy-efficient outdoor operation using ambient natural light.
Implementation Method 1
an optical component for reflecting light with a specific wavelength and transmitting other light; a cholesteric liquid crystal layer in a planar state for reflecting the light with the specific wavelength and transmitting the other light
Implementation Method 2
a first 1⁄4 wave plate between the first GH liquid crystal cell and the cholesteric liquid crystal layer in an extension direction of a screw axis of the cholesteric liquid crystal layer; and a second 1⁄4 wave plate between the second GH liquid crystal cell and the cholesteric liquid crystal layer in the extension direction of a screw axis of the cholesteric liquid crystal layer, wherein the first 1⁄4 wave plate and the second 1⁄4 wave plate are used for converting the linearly polarized light into circularly polarized light which has the same optical rotation characteristic as that of the cholesteric liquid crystal layer
Implementation Method 3
a first Guest Host (GH) liquid crystal cell and a second GH liquid crystal cell located at two opposite sides of the optical component, the first GH liquid crystal cell and the second GH liquid crystal cell each comprising a plurality of pixel units which have a first operation state and a second operation state, the pixel units transmitting natural light under the first operation state and transmitting linearly polarized light under the second operation state
Implementation Method 4
When the pixel units are under the second operation state, a polarization direction of the light reflected by the optical component is substantially perpendicular to an extension direction of a polarization axis of the pixel units, thereby achieving a dark state display
Data Source
AI summary
A display panel provided according to the present disclosure may include an optical component and two Guest Host liquid crystal cells located at two opposite sides of the optical component. The optical component is used for reflecting light with a specific wavelength and transmitting other light. The Guest Host liquid crystal cells each include a plurality of pixel units each having two operation states of transmitting natural light and linearly polarized light. When the pixel units transmit the linearly polarized light, the light reflected by the optical component cannot pass through the pixel units, thereby achieving a dark state display.