Diffraction Grating Device Using Destructive Interference for High Efficiency
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Solution Overview
Problem
Existing diffraction grating devices face challenges in achieving high diffraction efficiency, reducing volume, ensuring wide view angles, and minimizing chromatic dispersion while maintaining low production costs.
Innovation Solution
The development of a diffraction grating device with a light reflection substrate and a diffraction grating comprising diffraction elements that cause destructive interference between light rays reflected from the top and bottom surfaces, along with a dielectric layer of specific refractive index and structure, allowing for varied grating angles and auxiliary elements to enhance diffraction efficiency and reduce volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional diffraction gratings are used, then spectral function is achieved, but diffraction efficiency is insufficient
Solution Approach 1:
The patent uses a composite structure combining a dielectric layer with refractive index 1.3-2.0 and a light reflection substrate (such as Bragg reflector with alternating high/low refractive index layers). This composite design enables destructive interference of reflected light rays at specific wavelengths, achieving high diffraction efficiency while maintaining structural feasibility
Solution Approach 2:
The patent optimizes specific parameters including dielectric layer thickness (integer multiple of wavelength), diffraction element height (controlling path difference for destructive interference), and refractive index matching between layers. These parameter changes transform conventional low-efficiency gratings into high-efficiency devices
2Volume of moving object
If diffraction grating volume is reduced, then compact optical apparatus is achieved, but view angle may be limited
Solution Approach 1:
The patent transitions from conventional surface-level diffraction to a layered three-dimensional structure with controlled light paths through multiple interfaces. By manipulating light reflection and interference in the vertical dimension (through layer thickness and element height), the grating achieves compact volume while maintaining wide angular acceptance through optimized interference conditions
3Object-affected harmful factors
If large area diffraction grating is manufactured, then chromatic dispersion is reduced, but production cost increases
Solution Approach 1:
The patent segments the diffraction grating into repetitive unit cells (diffraction elements with main and auxiliary components) that can be manufactured independently and then assembled or patterned across large areas. This modular segmentation enables cost-effective large-scale production while maintaining consistent optical properties that reduce chromatic dispersion
Solution Approach 2:
The patent uses template-based replication or photolithographic patterning to copy the diffraction element pattern across the entire grating surface. This copying approach allows large-area gratings to be manufactured with high precision at low cost, avoiding the need for expensive custom fabrication of each element
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 achieves increased diffraction efficiency, reduced volume, and minimized chromatic dispersion, enabling the creation of compact optical apparatuses with wide view angles and cost-effective large-area diffraction grating devices.
Implementation Method 1
each diffraction element from among the plurality of diffraction elements having a height that causes a destructive interference between first light rays reflected by a top surface thereof and second light rays reflected by a bottom surface thereof
Implementation Method 2
a thickness of the dielectric layer is an integer multiple of a wavelength of light incident on the diffraction grating
Implementation Method 3
The light reflection substrate may be a Bragg reflector comprising dielectrics having refractive indexes different from one another
Data Source
AI summary
Provided are a diffraction grating device, a method of manufacturing the diffraction grating device, and an optical apparatus including the diffraction grating device. The diffraction grating device includes a diffraction grating arranged on a light reflection substrate. The diffraction grating includes a plurality of diffraction elements, each diffraction element from among the plurality of diffraction elements having a height that causes a destructive interference between first light rays reflected by a top surface therefore and second light rays reflected by a bottom surface thereof, the first and second light rays being incident on the top and bottom surfaces, respectively, at an incidence angle greater than 45°.