Photonic Integrated Multi-Beam Light Engine for Augmented Reality Displays and LiDAR Systems
Sensors, Devices and Components
Ref.-No.: 1401-6617-WT
Background
Conventional AR glasses and LiDAR systems rely on discrete optical components - lasers, mirrors, lenses - arranged in complex, bulky assemblies. This setup limits miniaturization, increases manufacturing cost, and imposes performance constraints such as restricted field of view (FOV), slow scanning speeds, and limited resolution. Laser-scanning systems offer advantages in brightness and contrast but are hindered by trade-offs between mirror size, scanning frequency, and laser modulation rates. Multi-beam scanning improves resolution but typically requires more lasers, further complicating integration. In LiDAR, conventional designs struggle with packaging and optical losses, especially in compact mobile or wearable form factors. A fully integrated photonic solution is therefore highly desirable for both AR and sensing applications.
Technology
The invention centers on a photonic integrated circuit (PIC) that integrates red, green, blue (RGB), and near-infrared (NIR) lasers directly onto a silicon-based chip. These lasers are coupled to waveguides fabricated from materials such as silicon nitride (SiN) or aluminum oxide, which guide the light with low loss across the chip. The waveguides terminate at precision-engineered edge couplers, located on a thin, suspended bridge region of the chip. These couplers emit multiple collimated beams into free space, each beam addressing a unique portion of the field of view. A two-axis MEMS mirror then scans these beams, and after passing twice through a lens system (double-pass configuration), the beams are directed into an optical waveguide combiner for display or reflected back for detection in LiDAR mode.
Figure 1: Schematic of a laser-scanning AR display: Modulated RGB laser beams are combined and scanned by a 2-axis MEMS mirror, then directed via relay optics into a waveguide combiner. The waveguide projects collimated light to the eye, forming an image based on beam angles.
Figure 2: Front view of a waveguide combiner: RGB light enters via the input coupler, propagates by total internal reflection, and is replicated by pupil elements before exiting through the output coupler toward the eye.
This configuration supports the emission of multiple beams in parallel, significantly boosting resolution and scan rate without increasing the number of laser sources. Additional on-chip elements include optical modulators for high-speed intensity modulation and optical switches for beam multiplexing. The architecture is optimized for low crosstalk, minimal optical aberration, and alignment-free packaging. Furthermore, the platform enables dual-functionality - simultaneous AR image projection and 3D environmental sensing - using shared optical paths and chip-level integration, significantly reducing size, weight, and system complexity.
Advantages
- Compact Integration: Combines lasers, optics, and waveguides on a single chip, minimizing system volume.
- High Resolution: Multi-beam scanning increases image sharpness and FOV without requiring ultra-fast mirrors or modulators.
- Dual Functionality: Supports both AR display and LiDAR sensing in one platform, reducing hardware redundancy.
- Efficient Optics: Double-pass lens design simplifies alignment and reduces the number of components.
- Scalable Manufacturing: Compatible with wafer-scale processes for cost-effective mass production
Potential applications
- AR/MR Glasses: Compact light engines for high-resolution visual overlays.
- Mobile Devices: Depth sensing and 3D mapping in smartphones or tablets.
- Automotive LiDAR: Miniaturized modules for navigation and object detection.
- Robotics: Integrated vision and distance measurement for smart automation.
- Medical Devices: AR-assisted diagnostics and surgical guidance tools.
PDF Download
- Ref.-No.: 1401-6617-WT (476.7 KiB)
Contact
Senior Patent- & License Manager
PD Dr. Wolfgang Tröger
Physicist
Phone: +49 89 / 29 09 19-27
Email:
troeger@max-planck-innovation.de
