Quantum Dot Polarizer for LCD Brightness and Color Gamut
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal displays (LCDs) face significant optical loss due to the use of red, green, and blue color filters, which absorb most of the visible spectrum, resulting in reduced brightness and efficiency.
Innovation Solution
Integration of quantum dots with a polarizing film, including a wavelength selecting layer to recycle blue light and a reflective polarizing layer to enhance brightness by reflecting light absorbed by the bottom polarizer, along with a light re-emitting layer comprising sub-cells emitting different wavelength ranges to improve color gamut and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If red, green and blue color filters are used to separate white light into color components, then color image formation is achieved, but optical loss increases significantly (70% absorption of visible spectrum)
Solution Approach 1:
The patent replaces traditional color filters with quantum dot materials that have different emission characteristics. Quantum dots convert blue light into red and green wavelengths through photoluminescence, achieving color separation with minimal energy loss compared to absorptive color filters
Solution Approach 2:
The patent converts the previously harmful absorption loss into beneficial photoluminescence conversion. Instead of absorbing and wasting light energy, the quantum dot layer converts blue light into useful red and green wavelengths, turning the energy loss problem into an efficient color generation solution
2Illumination intensity
If a bottom polarizer is used to polarize light, then polarization function is achieved, but brightness is reduced due to light absorption
Solution Approach 1:
The patent converts the previously harmful absorbed light into useful illumination by placing a quantum dot layer on the bottom polarizer. The quantum dots convert the polarized light (including previously absorbed wavelengths) into red and green components, recovering energy that would have been lost and increasing overall brightness
Solution Approach 2:
The quantum dot layer acts as an intermediary between the bottom polarizer and the liquid crystal cell. It converts the polarized light from the bottom polarizer into multiple color components, mediating the energy transfer and enabling both polarization function and enhanced brightness
3Quantity of substance
If quantum dots are placed near the light source, then color gamut is improved, but heat generation reduces quantum dot efficiency
Solution Approach 1:
The patent moves the quantum dot layer from the traditional location near the light source to the bottom polarizer location, effectively changing the spatial dimension of placement. This positions quantum dots away from the heat-generating light source while maintaining their color generation function, thus improving color gamut without excessive heat exposure
4Illumination intensity
If blue light is allowed to pass through the display, then brightness is maintained, but color accuracy is compromised
Solution Approach 1:
The patent changes the wavelength parameters of the light passing through the display by using quantum dot photoluminescence conversion. Blue light is converted into red and green wavelengths with specific emission peaks, achieving accurate color representation while maintaining overall brightness through efficient energy conversion
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 reduces optical loss, increases display brightness, and achieves high color gamut efficiency by effectively recycling and reflecting light, thereby enhancing the overall performance of the LCD.
Implementation Method 1
The first sub-cell comprises a first light re-emitting material configured to emit a first light component in a first wave-length range in response to the excitation light... the first re-emitting material comprises a first quantum dot material arranged to emit the first light component
Implementation Method 2
the optical film comprises a wavelength selecting layer configured to reflect light in the first wavelength range and light in the second wavelength range and to transmit light in the third wavelength range... blue light generated from blue backlight or blue quantum dots can be recycled inside the backlight module
Implementation Method 3
Also a reflective polarizing layer made upon the quantum dot layer can increase the brightness by reflect the light that is normally absorbed by a bottom polarizer
Data Source
AI summary
A polarizer component has an optical film to receive excitation light, a light re-emitting layer and a polarizing layer. The light re-emitting layer has quantum dots that re-emit red light and quantum dots that re-emit green light in response to the excitation light. The re-emitted red light is provided to a red sub-pixel to be filtered by a red color filter, and the re-emitting green light is provided to a green sub-pixel to be filtered by a green color filter. The excitation light can be blue or ultra violet and part of the excitation light is provided to a blue sub-pixel. The polarizing layer can be a reflective polarizing layer and the optical film can be a wavelength selecting layer. The light re-emitting layer may contain scattering particles to diffuse the excitation light provided to a blue sub-pixel.