Quantum Rod Polarizer with Protective Layer for LCD Backlight
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Solution Overview
Problem
Conventional liquid crystal display polarizers suffer from low light utilization and color gamut due to the absorption of non-polarized light, and quantum rod layers in backlights are prone to environmental degradation and heat-induced fading, leading to insufficient polarization efficiency.
Innovation Solution
An integral polarizer comprising a polarizing layer and a quantum rod layer with a protective layer to enhance light transmission and polarization, eliminating the need for additional optical films and maintaining a thin backlight unit, while the protective layer shields the quantum rods from environmental factors and heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a quantum rod layer is disposed in the backlight unit, then light utilization is enhanced, but the quantum rods are susceptible to oxygen and moisture causing decreased durability
Solution Approach 1:
The patent introduces a protective layer as an intermediary between the quantum rod layer and the ambient environment. This protective layer acts as a barrier that prevents oxygen and moisture from reaching the quantum rods, thereby maintaining their durability while preserving the high light utilization efficiency of the quantum rod layer in the backlight unit
Solution Approach 2:
The patent employs a thin film protective layer that covers the quantum rod layer. This thin film structure provides effective protection against environmental degradation while minimizing the increase in backlight unit thickness, thus maintaining both durability and optical performance
2Loss of energy
If a quantum rod layer is disposed in the backlight unit close to the light source, then light utilization is enhanced, but heat generated from the light source causes heat fading decreasing fluorescent efficiency
Solution Approach 1:
The protective layer serves as a thermal barrier between the light source and the quantum rod layer. It reduces the direct thermal impact from the backlight unit's light source on the quantum rods, minimizing heat fading and maintaining fluorescent efficiency while allowing the quantum rod layer to remain in its optimal position for light utilization
Solution Approach 2:
The patent applies protective layering in advance before the quantum rod layer is exposed to excessive heat from the light source. This pre-established protective structure cushions the quantum rods against thermal degradation, preserving their fluorescent properties throughout operation
3Loss of energy
If a quantum rod layer is disposed in the backlight unit with multiple optical films, then light utilization is enhanced, but the emitted polarized light is reflected and refracted decreasing polarization and directionality
Solution Approach 1:
The patent extracts the quantum rod layer from the complex multi-film backlight unit structure and positions it directly adjacent to the polarizer. This extraction eliminates the interference of multiple optical films (diffuser films, brightness enhancement films, prism sheets) that cause reflection and refraction, thereby maintaining high polarization efficiency and directionality while preserving light utilization benefits
4Loss of energy
If brightness enhancement film and prism film are combined to recirculate light, then light efficiency is enhanced, but the thickness of the backlight unit increases
Solution Approach 1:
The patent merges the light recirculation function with the polarizer assembly by positioning the quantum rod layer directly on the polarizer. This integration eliminates the need for separate brightness enhancement films and prism films, achieving light efficiency enhancement while maintaining a thin backlight unit structure
Solution Approach 2:
The quantum rod layer serves multiple functions simultaneously: it acts as a polarized light source, a wavelength converter, and a protective element when integrated with the polarizer. This multi-functionality replaces the need for multiple separate optical films, reducing overall thickness while maintaining light efficiency
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 solution significantly improves light utilization and color gamut without increasing the backlight unit thickness, maintaining polarization efficiency and extending the durability of the quantum rod layer.
Implementation Method 1
The quantum rod is a nano-scale semiconductor material. It is in a shape of a one-dimensional rod-like structure. The major axis direction of the quantum rod is able to absorb the non-polarized light to emit a polarized light with a wavelength longer than the original non-polarized light.
Implementation Method 2
the semiconductor material of the quantum rods is susceptible to be adversely affected by oxygen and moisture in ambient environment to result in decreased durability thereof
Implementation Method 3
When, in a liquid crystal display, the non-polarized light emitted from the backlight is incident onto the absorptive polarizers, the incident light with a direction parallelly to the absorption axis direction of the polarizers is absorbed and not transmitted.
Implementation Method 4
The major axis direction of the quantum rod is able to absorb the non-polarized light to emit a polarized light with a wavelength longer than the original non-polarized light
Data Source
AI summary
Disclosed herein is a polarizer for LCD. The polarizer includes a polarizing layer, a quantum rods layer comprising a plurality of quantum rods, a first protective layer and a second protective layer, wherein major axis of the quantum rods is aligned in a direction perpendicular to the absorption axis of the polarizing layer. Accordingly, the incident unpolarized light emitted from the backlight unit can be transferred to be polarized light by the quantum rods layer and pass through the polarizing layer directly for enhancing the utility of the backlight.