Quantum Dot Liquid Crystal Display Side Visibility
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges with side visibility defects and parallax mixing due to the use of color filters, which complicate the structure and increase manufacturing costs, while dividing pixel electrodes into sub-pixels complicates the design and reduces luminance.
Innovation Solution
The use of quantum dot particles instead of color filters, combined with a liquid crystal layer and dichroic dye, to improve side visibility and reduce mixing defects by scattering and converting light wavelengths, and omitting at least one polarizer to simplify the structure and reduce thickness and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If color filters are used in LCD devices, then desired colors can be obtained by filtering white light, but side visibility defects occur and structure becomes complicated
Solution Approach 1:
The patent removes the color filter layer from the traditional LCD structure and replaces it with quantum dot particles dispersed in the liquid crystal layer. This extraction of the color filter component simplifies the overall device structure while maintaining color display capability through the quantum confinement effect of quantum dots, which emit specific wavelengths when excited by blue light.
Solution Approach 2:
The patent changes the physical state and optical properties of the liquid crystal layer by dispersing quantum dot particles within it. This parameter change allows the liquid crystal layer itself to perform color filtering functions through wavelength conversion, eliminating the need for separate color filter layers and improving side visibility through enhanced light scattering.
2Illumination intensity
If pixel electrodes are divided into sub-pixel electrodes to improve side visibility, then side visibility improves, but manufacturing cost increases and luminance decreases
Solution Approach 1:
The patent introduces quantum dot particles as an intermediary substance within the liquid crystal layer to improve side visibility. These particles scatter light effectively in the vertical direction, enhancing side visibility without requiring complex sub-pixel electrode divisions. The quantum dots act as a mediator between the blue light source and the final displayed colors, providing both visibility improvement and color generation.
3Illumination intensity
If an upper polarizer is added to control transmittance, then transmittance control improves, but distance between liquid crystal layer and quantum dot particles increases causing parallax mixing defects
Solution Approach 1:
Instead of adding an upper polarizer to control transmittance, the patent inverts the approach by using the quantum dot particles themselves and the liquid crystal layer's optical properties to control light transmission. The liquid crystal layer's ability to rotate polarization and the quantum dots' wavelength conversion properties work together to control transmittance without increasing device thickness, thereby preventing parallax mixing defects.
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 approach enhances side visibility, reduces mixing defects, and simplifies the LCD device structure, lowering manufacturing costs by eliminating the need for additional polarizers and complex pixel electrode divisions.
Implementation Method 1
Quantum dot particles receive light of a particular wavelength and emit light having a different wavelength from that of the received light
Implementation Method 2
Light emitted from quantum dot particles is scattered and may thus improve the side visibility of an LCD device
Implementation Method 3
Quantum dot particles not only scatter light, but also change the polarization state of light
Implementation Method 4
a liquid crystal layer interposed between the first substrate and the second substrate and including a liquid crystal and a dichroic dye
Implementation Method 5
The LCD device generally includes two polarizers at the top and the bottom of a liquid crystal layer to adjust the amount of light transmitted therethrough
Data Source
AI summary
A display device includes a plurality of pixels; a first substrate including a pixel electrode disposed in a pixel of the plurality of pixels, a second substrate facing the first substrate and including a color adjusting pattern, which is disposed in the pixel of the plurality of pixels, and a common electrode, which is disposed on the color adjusting patterns, and a liquid crystal layer interposed between the first substrate and the second substrate and including a liquid crystal and a dichroic dye, wherein the plurality of pixels include a first-color pixel, which is configured to display a first color, and a second-color pixel, which is configured to display a second color different from the first color, and the color adjusting pattern includes a first color adjusting pattern, which is disposed in the first-color pixel, and a second color adjusting pattern, which is disposed in the second-color pixel.