Display Panel With Waveguide And Grating Layer
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Solution Overview
Problem
Existing liquid crystal display devices face issues with low transmittance and large liquid crystal cell thickness, which reduces response speed and requires polarizers for grayscale and color display, making them thick and inefficient.
Innovation Solution
A display panel design featuring a first and second substrate with a liquid crystal layer, a waveguide layer, and a grating layer, where electrodes adjust the refractive index of the liquid crystal layer to control light coupling efficiency and direction, eliminating the need for polarizers and color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polarizers are used to achieve grayscale display in liquid crystal display devices, then grayscale control is achieved, but transmittance is reduced to about 7%
Solution Approach 1:
The patent removes polarizers from the display structure entirely, extracting the problematic component that caused low transmittance. Instead of using polarizers for grayscale control, the invention employs a different mechanism based on liquid crystal birefringence and optical interference, achieving grayscale display without the transmittance penalty of polarizing filters
Solution Approach 2:
The patent changes the fundamental operating parameters by eliminating the polarizer-based grayscale mechanism and replacing it with a system that controls light through liquid crystal refractive index modulation and optical path difference, fundamentally altering how grayscale is achieved and thereby improving transmittance
2Stability of the object's composition
If liquid crystal cell thickness is increased to 3 μm to 5 μm, then structural stability is improved, but response speed is reduced
Solution Approach 1:
The patent optimizes the liquid crystal cell thickness parameter to a specific range that balances structural stability with fast response speed, moving away from the conventional 3-5 μm thickness. This parameter optimization, combined with the new optical mechanism, achieves both stability and speed requirements
3Ease of operation
If color resistors are added on the color filter substrate to realize color display, then color display capability is achieved, but the display panel becomes thick
Solution Approach 1:
The patent removes traditional color filter layers with color resistors from the display structure, extracting the component that added thickness. Instead, color display is achieved through a different mechanism involving liquid crystal optical properties and interference effects, eliminating the need for thick color filter assemblies
Solution Approach 2:
The invention changes the approach to color display by eliminating the color filter layer and using alternative optical mechanisms, thereby reducing the z-direction thickness of the display panel while maintaining color display functionality
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 design enhances transmittance, reduces liquid crystal cell thickness, and improves response speed while enabling grayscale and color display without polarizers or color filters, resulting in a more efficient and thinner display panel.
Implementation Method 1
the liquid crystal layer, a first electrode, a second electrode, a waveguide layer and a grating layer that are between the first substrate and the second substrate; the first electrode and the second electrode are configured to adjust a refractive index of the liquid crystal layer by changing voltages applied thereto
Implementation Method 2
a coupling efficiency at which light is coupled out of the waveguide layer is determined according to a difference between a refractive index of the grating layer and the refractive index of the liquid crystal layer
Data Source
AI summary
A display panel and a display device are disclosed and belong to the field of display technology. The display panel comprises a first substrate and a second substrate opposite to each other, and a liquid crystal layer, a first electrode, as second electrode, a waveguide layer and a grating layer between the first and second substrates; wherein the waveguide layer is on a side of the liquid crystal layer proximal to the first substrate; and the grating layer is in contact with the liquid crystal layer; the first electrode and the second electrode are configured to adjust a refractive index of the liquid crystal layer by changing voltages applied thereto; and a coupling efficiency at which light is coupled out of the waveguide layer is determined according to a difference between a refractive index of the grating layer and the refractive index of the liquid crystal layer.