Liquid Crystal Grating Light Outcoupling Control
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Solution Overview
Problem
Current display technologies face challenges in achieving high resolution and precision in light outcoupling and direction control, leading to issues with grayscale display and light leakage in dark states, particularly in the absence of polarizers.
Innovation Solution
A display panel incorporating a liquid crystal layer sandwiched between substrates with a control electrode that forms a liquid crystal grating to control light propagation through total reflection, allowing for selective light coupling and diffraction, enabling multi-grayscale display and preventing light leakage by adjusting electric fields and refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a liquid crystal grating is used to control light outcoupling, then display resolution and precision are improved, but device complexity increases due to the need for control electrodes and electric field management
Solution Approach 1:
The patent utilizes changes in the refractive index parameter of the liquid crystal material in response to electric field strength. By varying the voltage applied to the control electrode, the refractive index of the liquid crystal grating is dynamically adjusted, enabling precise control over light outcoupling and direction without requiring complex mechanical structures.
Solution Approach 2:
The patent replaces mechanical light modulation mechanisms with an electro-optic system. Instead of using mechanical moving parts or physical masks to control light, the invention uses electric fields to modify the refractive index of the liquid crystal, thereby controlling light propagation and outcoupling precision through optical means rather than mechanical means.
2Object-generated harmful factors
If total internal reflection is used to guide light, then light leakage is reduced, but manufacturing precision requirements increase for substrate interfaces
Solution Approach 1:
The patent employs total internal reflection by carefully controlling the refractive index parameters of the liquid crystal layer and surrounding substrates. By ensuring that the refractive index of the liquid crystal is higher than that of the substrates, and by controlling the incident angle of light, the system achieves efficient light guidance with minimal leakage, balancing manufacturing feasibility with optical performance.
3Device complexity
If polarizers are eliminated, then device complexity and manufacturing cost are reduced, but control over light polarization and direction becomes more difficult
Solution Approach 1:
The patent replaces the function of polarizers with an electro-optic control mechanism. Instead of using physical polarizing filters that mechanically block certain light directions, the invention uses voltage-controlled refractive index changes in the liquid crystal to steer and control light propagation, achieving polarization and direction control through electric fields rather than mechanical filters.
Solution Approach 2:
The liquid crystal grating structure serves multiple functions simultaneously: it acts as both a light guide and a polarization control element. By combining the waveguide function with the polarization modulation capability in a single material system, the patent eliminates the need for separate polarizer components while maintaining control over light properties.
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 enhances display resolution and precision by controlling light outcoupling and direction, eliminates the need for polarizers, and improves contrast by ensuring no light emission in dark states, thus enhancing image quality and productivity.
Implementation Method 1
a liquid crystal layer (100) disposed at a side of the control electrode (60) proximate to the optical waveguide (10), wherein the control electrode (60) is configured to receive electrical signals to control light incident into the liquid crystal layer (100) to propagate through total reflection, or form a liquid crystal grating (30) to make totally-reflected light in the liquid crystal layer (100) coupled out at a side of the first substrate (11)
Implementation Method 2
The light-guide is configured to guide light, through internal reflections, between first and second oppositely located outer boundaries of the light-guide
Data Source
Figure 1~3
Figure 4~5b
Figure 5c~7
AI summary
A display panel (01) includes a liquid crystal layer (100), a first substrate (11) and a second substrate (12) that are disposed at opposite sides of the liquid crystal layer (100), and a control electrode (60) disposed above the first substrate (11). The control electrode (60) is configured to receive electrical signals to control light incident into the liquid crystal layer (100) to propagate through total reflection, or to form a liquid crystal grating (30) to make totally-reflected light in the liquid crystal layer (100) coupled out at a side of the first substrate (11).