Waveguide Light Projection with Grating Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current light projecting technologies are hindered by high costs, large size, and integration challenges, which limit their application in devices such as 3D camera modules for facial recognition and other functionalities.
Innovation Solution
A light projecting system utilizing a waveguide with grating structures and a reflective layer, where the grating structures disrupt total internal reflection to couple out light beams, allowing for efficient light projection with a single laser source and integration on a substrate, reducing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional light projecting technologies are used, then light projection functionality is achieved, but cost is high
Solution Approach 1:
The patent combines the light projection function with a waveguide structure that integrates multiple components (grating structures, reflective layers, light-absorbing materials) into a single substrate. This merging of functions reduces the number of separate components needed, thereby lowering manufacturing cost while maintaining light projection functionality.
Solution Approach 2:
The patent modifies the optical parameters of the waveguide by incorporating grating structures with specific periods, depths, and duty cycles, along with reflective layers and light-absorbing materials. These parameter changes enable efficient light coupling and projection while using cost-effective materials and fabrication processes.
2Reliability
If traditional light projecting technologies are used, then light projection functionality is achieved, but device size is large
Solution Approach 1:
The patent embeds the light projection mechanism within a waveguide substrate, nesting the grating structures, reflective layers, and light-absorbing materials inside the waveguide volume. This nested arrangement compactly integrates all necessary components, significantly reducing the overall device size while preserving light projection functionality.
Solution Approach 2:
The patent transitions from traditional planar light projection to a three-dimensional waveguide structure where light propagates through the bulk of the substrate. By utilizing the vertical dimension and creating multiple reflection paths within the waveguide thickness, the system achieves compact integration without compromising projection performance.
3Reliability
If traditional light projecting technologies are used, then light projection functionality is achieved, but integration is low
Solution Approach 1:
The patent merges multiple optical functions (light coupling, total internal reflection, light extraction, and projection) into a single integrated waveguide structure. The grating structures, reflective layers, and light-absorbing materials work together as a unified system, eliminating the need for separate components and improving integration.
Solution Approach 2:
The waveguide substrate serves multiple functions simultaneously: it acts as a light guide, a structural platform for grating structures, a medium for total internal reflection, and an integration substrate for reflective layers and light-absorbing materials. This multi-functionality reduces system complexity and improves integration.
4Productivity
If grating structures are used to couple out light, then light projection efficiency is improved, but zeroth-order diffraction interference occurs
Solution Approach 1:
The patent converts the harmful zeroth-order diffraction effect into a beneficial element by strategically placing light-absorbing material layers at specific positions within the waveguide. These layers absorb the unwanted zeroth-order diffraction light, transforming it from a harmful interference into a controlled energy dissipation that enhances overall projection quality.
Solution Approach 2:
The reflective layers and light-absorbing materials act as intermediary elements between the grating structures and the output. These intermediaries selectively manage different diffraction orders, allowing useful higher-order diffraction to proceed while intercepting and absorbing harmful zeroth-order diffraction, thereby resolving the interference issue.
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 system achieves efficient light projection with reduced size and manufacturing costs, enabling effective 3D feature detection and mapping applications while avoiding zeroth-order diffraction interference.
Implementation Method 1
The waveguide is configured to guide an in-coupled light beam to undergo total internal reflection between the first surface and the second surface
Implementation Method 2
The grating structures are configured to disrupt the total internal reflection to cause at least a portion of the in-coupled light beam to couple out of the waveguide
Implementation Method 3
The waveguide further comprises a reflective layer disposed on the second surface and covering the first grating structures
Data Source
AI summary
A waveguide comprises a first surface and a second surface. The second surface comprises a first plurality of grating structures. The waveguide is configured to guide an in-coupled light beam to undergo total internal reflection between the first surface and the second surface. The grating structures are configured to disrupt the total internal reflection to cause at least a portion of the in-coupled light beam to couple out of the waveguide from the first surface, the portion of the in-coupled light beam coupled out of the waveguide forming out-coupled light beams. The waveguide further comprises a reflective layer disposed on the second surface and covering the first grating structures.