Polarizer-Free Liquid Crystal Display Using Diffractive Optical Elements
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Solution Overview
Problem
Conventional liquid crystal display devices have a low light utilization rate due to the need for polarizers with perpendicular transmission axes, limiting the amount of light that can pass through to around 50%.
Innovation Solution
A display device with a liquid crystal cell divided into portions that rotate in different planes, utilizing a diffractive optical element with a refractive index matching the short-axis refractive index of the liquid crystal, and a control element to manage the electric field for polarized light diffraction, eliminating the need for polarizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional liquid crystal display devices use polarizers with perpendicular transmission axes to control light transmission, then grayscale display can be achieved, but the light utilization rate is limited to around 50%
Solution Approach 1:
The liquid crystal cell is divided into a first portion and a second portion, where liquid crystal molecules in the first portion rotate in a first plane and molecules in the second portion rotate in a second plane perpendicular to the first plane. This segmentation allows different portions to manipulate different polarized components of light independently, enabling both polarized components to be utilized for display and achieving light utilization rates exceeding 50%.
Solution Approach 2:
The invention introduces a new dimension of control by dividing the liquid crystal cell into portions that rotate in perpendicular planes (first plane and second plane). This dimensional approach allows the device to manipulate both polarized components of light simultaneously, transforming the traditional single-plane rotation limitation into a multi-plane rotation system that improves light utilization.
2Ease of operation
If polarizers are used to control light transmission in liquid crystal display devices, then grayscale display is achieved, but the device structure becomes more complex
Solution Approach 1:
The invention extracts and eliminates the polarizers from the conventional liquid crystal display structure. By using a liquid crystal cell with portions rotating in perpendicular planes, the device can control both polarized components of light without requiring external polarizers, thereby simplifying the overall device structure while maintaining grayscale control capability.
Solution Approach 2:
The liquid crystal cell structure is designed to perform multiple functions: it can control both polarized components of light, achieve grayscale display, and eliminate the need for separate polarizer components. The first and second portions of the liquid crystal cell work together to provide comprehensive light control in a unified structure.
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 significantly improves light utilization efficiency by allowing both polarized components to be used for display, potentially exceeding 50% light usage without polarizers.
Implementation Method 1
a diffractive optical element in the liquid crystal layer... so that the diffractive optical element diffracts a first polarized component of light propagating in the light guide plate of the backlight module out of the light guide plate
Implementation Method 2
Liquid crystal molecules of the first portion are capable of rotating in a first plane. Liquid crystal molecules of the second portion are capable of rotating in a second plane perpendicular to the first plane
Implementation Method 3
The rotation of the liquid crystal may be controlled using a voltage to control the amount of light transmitted through the upper polarizer, thereby achieving grayscale display
Implementation Method 4
A refractive index of the diffractive optical element is equal to a short-axis refractive index of a liquid crystal in the liquid crystal layer
Data Source
AI summary
A display device and a method for controlling the display device are disclosed. The display device includes a backlight module and a liquid crystal cell on a light emitting side of the backlight module. The liquid crystal cell includes a first electrode, a second electrode disposed in a first direction opposite to the first electrode, a liquid crystal layer between the first electrode and the second electrode, and a diffractive optical element in the liquid crystal layer. A refractive index of the diffractive optical element is equal to a short-axis refractive index of a liquid crystal in the liquid crystal layer. The liquid crystal cell is divided into a first portion where the liquid crystal molecules are capable of rotating in a first plane and a second portion in a second direction perpendicular to the first direction where liquid crystal molecules are capable of rotating in a first plane.