Wavelength Conversion Element for Display Light Efficiency
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Solution Overview
Problem
Display devices with a backlight unit and a liquid crystal display panel face efficiency issues due to the absorption of unwanted wavelengths by the color filter, leading to reduced light emission and increased power consumption.
Innovation Solution
Incorporating a wavelength conversion element, such as quantum dots, between the liquid crystal layer and the backlight unit, which converts monochromatic light into desired wavelengths, improving light utilization and reducing power consumption by eliminating the need for color filters that absorb unwanted wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a color filter is used to select specific wavelengths, then color display is achieved, but light efficiency deteriorates due to absorption of cut wavelength ranges
Solution Approach 1:
The patent converts the harmful absorption effect of color filters into a beneficial wavelength conversion process. Instead of absorbing unwanted wavelengths and losing energy, the invention uses wavelength conversion elements to actively transform the spectrum, converting light from the backlight unit into desired wavelengths with higher efficiency and without energy loss through absorption.
Solution Approach 2:
The patent changes the fundamental parameter of wavelength selection from passive absorption (color filters) to active conversion (wavelength conversion elements). This parameter change enables the system to transform light wavelengths directly, achieving the desired spectral distribution without the energy losses inherent in absorption-based filtering.
2Illumination intensity
If a wavelength conversion element is introduced, then light efficiency improves, but device complexity increases
Solution Approach 1:
The patent merges the wavelength conversion element with existing components in the display device, such as integrating it with the backlight unit or the liquid crystal panel structure. This merging approach achieves wavelength conversion functionality without adding separate, complex subsystems, thereby improving light efficiency while minimizing increases in device complexity.
Solution Approach 2:
The wavelength conversion element is designed to perform multiple functions simultaneously: it converts wavelengths to achieve desired color output, acts as a spectral filter, and can be integrated with the existing display structure. This multi-functionality reduces the need for additional separate components, thereby improving light efficiency without proportionally increasing device complexity.
3Manufacturing precision
If quantum dots are used for wavelength conversion, then color display accuracy improves, but manufacturing difficulty increases
Solution Approach 1:
The patent controls the size and composition parameters of quantum dots to precisely tune their wavelength conversion characteristics. By adjusting these parameters, the invention achieves arbitrary emission wavelength control and high color display accuracy. The manufacturing process is designed to control these parameters within specific ranges to ensure consistent performance.
Solution Approach 2:
The patent employs preliminary actions in the manufacturing process, such as pre-synthesizing quantum dots with controlled size distributions and pre-aligning them in the wavelength conversion layer before final assembly. This preliminary preparation ensures that the quantum dots are properly positioned and oriented to achieve the desired wavelength conversion efficiency and color accuracy, thereby reducing manufacturing difficulty despite the precision requirements.
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 solution enhances light efficiency, reduces power consumption, and simplifies manufacturing by eliminating the need for additional retardation films, while allowing for arbitrary emission wavelength control and improved color display accuracy.
Implementation Method 1
a wavelength conversion element, such as quantum dots, between the liquid crystal layer and the backlight unit, which converts monochromatic light into desired wavelengths
Implementation Method 2
a wavelength conversion element located between the first pixel electrode and the first insulating substrate or between the first pixel electrode and the second insulating substrate, to convert light of a first wavelength polarized in a first polarization direction into light of a second wavelength polarized in a second polarization direction
Data Source
AI summary
According to one embodiment, a display device includes a first insulating substrate, a second insulating substrate, a first pixel electrode and a second pixel electrode, a wavelength conversion element to convert light of a first wavelength polarized in a first polarization direction into light of a second wavelength polarized in a second polarization direction, and a liquid crystal layer having a first thickness in an area opposed to the first pixel electrode, and having a second thickness greater than the first thickness in an area opposed to the second pixel electrode.