Photonic Integrated Circuit Wavelength Multiplexing for Compact Laser Projectors
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Solution Overview
Problem
Conventional laser projectors face challenges in aligning laser diodes, focusing lenses, and controllable mirrors to achieve optimal spot size and convergence, particularly in applications where form factor is a critical design consideration, such as wearable heads-up displays, leading to bulkier and less comfortable devices.
Innovation Solution
An optical engine design that integrates multiple laser diodes within a hermetically sealed package, using a photonic integrated circuit for wavelength multiplexing and collimation lenses for beam alignment, along with an optical director element and diffractive optical elements for focus correction, to produce a compact and efficient light projection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser projectors use separate packages for laser diodes and focusing lenses with tuned alignment, then optimal spot size and convergence are achieved, but the form factor becomes large and bulky
Solution Approach 1:
The patent integrates multiple laser diodes and focusing lenses onto a single photonic integrated circuit substrate, merging previously separate components into one unified structure. This integration maintains precise alignment through monolithic fabrication while dramatically reducing the overall form factor of the laser projector system.
Solution Approach 2:
The patent transitions from three-dimensional mechanical alignment of separate components to two-dimensional planar integration on a photonic circuit substrate. By redistributing components across the substrate plane with precise lithographic positioning, the system achieves high alignment precision without requiring bulky mechanical adjustment mechanisms.
2Reliability
If wearable heads-up displays use large components for optimal optical performance, then alignment and focus are maintained, but the device becomes bulkier and less comfortable
Solution Approach 1:
The patent combines multiple laser diodes, focusing lenses, and optical routing elements into a single integrated photonic circuit package. This integration maintains reliable optical performance through precise monolithic fabrication while significantly reducing the weight and size of wearable display components.
Solution Approach 2:
The patent changes the scale and configuration of optical components by integrating them at the photonic circuit level rather than using discrete macro-scale components. This parameter change enables compact, lightweight wearable devices while maintaining optical performance through sub-millimeter precision fabrication techniques.
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 optical engine enables compact, lightweight, and efficient light projection with improved alignment and focus, enhancing the form factor and user experience of wearable heads-up displays while maintaining optical performance.
Implementation Method 1
a photonic integrated circuit comprising a plurality of input facets and at least one output facet, in operation, the photonic integrated circuit receives a plurality of beams of light at the respective plurality of input facets and wavelength multiplexes the plurality of beams of light to provide an aggregated beam of light at the output facet
Implementation Method 2
Each input facet of the plurality of input facets may be a grating input coupler
Implementation Method 3
A collimation lens may be positioned and oriented to receive and collimate the aggregate beam of light from the output facet of the photonic integrated circuit
Implementation Method 4
at least one diffractive optical element positioned and oriented to receive the aggregate beam of light, in operation, the at least one diffractive optical element provides wavelength dependent focus correction for the aggregate beam of light
Data Source
AI summary
Systems, devices, and methods of manufacturing optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. Photonic integrated circuits having grating couplers thereon may be used to wavelength multiplex beams of light emitted by the plurality of laser diodes into a coaxially superimposed aggregate beam. Such optical engines may have various advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.