LCD Polarizer Light Recycling via Reflective Film
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Solution Overview
Problem
Liquid Crystal Displays (LCDs) suffer from low light efficiency due to about 50% of the backlight light being absorbed or reflected by the polarizer, resulting in decreased luminance.
Innovation Solution
A liquid crystal display design incorporating a transparent insulation substrate, a first polarizer with a light blocking film and metal wires, and a semiconductor layer, where the metal wires and light blocking film are patterned to reflect most of the light and transmit a portion of it, thereby increasing light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional polarizer is used in the LCD, then the polarization function is achieved, but about 50% of the backlight light is absorbed or reflected, resulting in low light efficiency and decreased luminance
Solution Approach 1:
The polarizer is segmented into multiple functional components: a light blocking film with metal wires for polarization, and a reflective film for light recycling. This segmentation allows different regions to perform different functions - the metal wire regions polarize light while the reflective regions return absorbed light back to the liquid crystal layer for a second polarization opportunity, thereby improving overall light efficiency without compromising polarization performance
Solution Approach 2:
Instead of discarding the light that is absorbed or reflected by the polarizer (which would be wasted energy), the invention recovers this light by introducing a reflective film that redirects it back through the liquid crystal layer and polarizer. This recovery mechanism allows the same light to be utilized multiple times, converting what would be energy loss into useful illumination and improving luminance
2Reliability
If the polarizer absorbs or reflects light to achieve polarization, then the polarization function is fulfilled, but light efficiency decreases and luminance is reduced
Solution Approach 1:
The reflective film enables continuous utilization of light by creating a closed-loop optical path where light that would otherwise be lost is redirected back through the polarization layers. This continuous action ensures that the polarization function remains reliable while maximizing the use of available light energy, as the same photons can undergo polarization multiple times rather than being discarded after a single pass
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 design enhances light efficiency by recycling reflected light, increasing the luminance of the LCDs by ensuring that substantially all light from the backlight unit is utilized.
Implementation Method 1
The blocking film reflects substantially all of the light
Implementation Method 2
Gaps disposed between the metal wires transmit part of the light
Data Source
AI summary
A liquid crystal display includes a transparent insulation substrate, a first polarizer, and a semiconductor layer, a thin film transistor, and a backlight unit. The first polarizer is disposed on the transparent insulation substrate. The first polarizer includes a light blocking film and metal wires. The semiconductor layer, disposed on the light blocking film, has a perimeter aligned with a perimeter of the light blocking film. The thin film transistor, disposed on the semiconductor layer, includes a source region and a drain region disposed in the semiconductor layer. The backlight unit, disposed under the transparent insulation substrate, provides light to the transparent insulation substrate. The blocking film reflects substantially all of the light. Gaps are disposed between the metal wires.