Waveguide Display Panel Grating Coupling Structures
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Solution Overview
Problem
Existing virtual and augmented reality displays, as well as transparent displays, face challenges in achieving high transparency and high Pixels Per Inch (PPI) due to limitations in traditional LCD and OLED panel structures, which hinder light transmittance and monocular focus.
Innovation Solution
A display panel design featuring an upper and lower substrate with a liquid crystal layer, a waveguide layer, grating coupling structures, and electrode structures, where the liquid crystal molecules have different refractive indices for o-polarized and e-polarized light, and the waveguide layer's refractive index is greater than adjacent film layers, allowing for collimated backlight incidence and efficient light coupling and direction control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditionally structured LCD and OLED panels are used, then display functionality is achieved, but light transmittance is reduced and transparency is degraded
Solution Approach 1:
The invention extracts and removes traditional display components (color filters, pixel electrodes, liquid crystal layers) that block light, retaining only the essential waveguide layer with grating structures. This extraction of unnecessary elements achieves high light transmittance (greater than 90%) while maintaining display functionality through optical diffraction principles
Solution Approach 2:
The invention replaces the mechanical/electrical control system of traditional LCDs (liquid crystal molecules, pixel electrodes, color filters) with an optical system based on grating diffraction. The grating structures on the waveguide surface diffract light to create images, eliminating the need for complex mechanical switching components and achieving high transparency
2Ease of operation
If traditional LCD and OLED panel structures are used, then display operation is achieved, but monocular focus and near-to-eye display are difficult to achieve
Solution Approach 1:
The invention applies local quality by creating spatially varying grating structures with different periods and orientations in different regions of the waveguide. These localized grating patterns control the direction and focus of diffracted light, enabling monocular focus and near-to-eye display while keeping the overall system simple
Solution Approach 2:
The waveguide layer acts as an intermediary between the light source and the user's eye. It receives collimated light, processes it through grating diffraction, and outputs focused light rays that converge at the user's pupil, enabling comfortable near-to-eye viewing without complex additional optical components
3Manufacturing precision
If display definition is increased, then display quality is improved, but fabrication process complexity increases making high PPI difficult to achieve
Solution Approach 1:
The invention transitions from controlling display resolution through pixel density (two-dimensional constraint) to controlling it through optical diffraction angles (angular dimension). The grating period and orientation determine the effective pixel resolution, allowing high PPI to be achieved through optical design rather than fabrication precision, thus simplifying manufacturing
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 light transmittance, achieves near-to-eye monocular focus, and facilitates high PPI displays by selectively converging light rays and controlling grayscale, potentially eliminating the need for color filters and using transparent materials for high transparency in virtual and augmented reality displays.
Implementation Method 1
a liquid crystal layer, a waveguide layer, a plurality of grating coupling structures, and a plurality of electrode structures. The liquid crystal layer is arranged between the upper substrate and the lower substrate, and liquid crystal molecules in the liquid crystal layer have a refractive index no with respect to o-polarized light, and a refractive index ne with respect to e-polarized light
Implementation Method 2
the plurality of electrode structures are arranged on sides of the grating coupling structures facing the upper substrate and are in correspondence to the grating coupling structures in a one-to-one manner
Implementation Method 3
the waveguide layer is arranged on a side of the lower substrate facing the upper substrate, and a refractive index of the waveguide layer is at least greater than a refractive index of a film layer in contact with the waveguide layer
Implementation Method 4
the plurality of grating coupling structures are arranged and arrayed on a surface of the waveguide layer on a side thereof facing the upper substrate; the plurality of electrode structures are arranged on sides of the grating coupling structures facing the upper substrate
Data Source
AI summary
The disclosure provides a display panel and a display device. The display panel includes an upper substrate (001) and a lower substrate (002) arranged opposite to each other, a liquid crystal layer (003), a waveguide layer (004), a plurality of grating coupling structures (005), and a plurality of electrode structures (006). The liquid crystal layer (003) is arranged between the upper substrate (001) and the lower substrate (002), and liquid crystal molecules in the liquid crystal layer (003) have a refractive index no with respect to o-polarized light, and a refractive index ne with respect to e-polarized light; the waveguide layer (004) is arranged on a side of the lower substrate (002) facing the upper substrate (001), and a refractive index of the waveguide layer (004) is at least greater than a refractive index of a film layer in contact with the waveguide layer (004); the plurality of grating coupling structures (005) are arranged and arrayed on a surface of the waveguide layer (004) on a side thereof facing the upper substrate (001); and the plurality of electrode structures (006) are arranged on sides of the grating coupling structures (005) facing the upper substrate (001) and are in correspondence to the grating coupling structures (005) in a one-to-one manner. The display and the display device can control a display grayscale.