2D Scanning Display with Co-Scanned 3D Mapping
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Solution Overview
Problem
Wearable displays, such as HMDs and NEDs, face challenges with bulkiness and discomfort due to large, unbalanced, and heavy designs, and there is a need for compact and efficient systems that can provide both virtual and augmented reality experiences while reducing size and weight.
Innovation Solution
A wearable display device using a scanning projector with a tiltable reflector that co-scans image and ranging beams, utilizing a pupil-replicating lightguide to convey scanned light to the user's eye and an optical ranging device to gather environmental information, including distance and object properties, while sharing the beam scanner for space and cost savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a traditional display panel and screen are used in HMD/NED, then the display can show images, but the device becomes large, bulky, and heavy
Solution Approach 1:
The patent removes the traditional display panel and screen from the system, extracting only the essential function of image generation. Instead of using a physical display panel, the system uses a scanning projector that generates images by scanning light beams directly into the user's eye, eliminating the need for intermediate screens and reducing overall device weight and size.
Solution Approach 2:
The patent replaces the mechanical display panel system with an optical scanning system. Instead of using a physical panel that requires mounting and support structures, the system uses a scanning projector with movable mirrors or acousto-optic deflectors to steer light beams, substituting mechanical panel structures with optical steering mechanisms that are more compact.
2Weight of stationary object
If a scanning projector is used to reduce size and weight, then the device becomes compact, but the system complexity increases due to beam scanning mechanisms
Solution Approach 1:
The patent implements a dual-function scanning system where the same beam scanner used for displaying images is also employed for environmental mapping and depth sensing. The scanning projector emits both visible light for display and infrared light for ranging, using identical optical steering components. This multi-functionality reduces the number of separate subsystems and simplifies the overall device architecture despite the advanced scanning capabilities.
Solution Approach 2:
The patent merges the display function with the environmental sensing function into a single integrated scanning projector system. The beam scanner, optical paths, and control electronics are combined to perform both image rendering and 3D environmental mapping simultaneously or in alternating fashion, reducing the total component count and system complexity compared to having separate display and sensing systems.
3Reliability
If separate systems are used for display and environmental scanning, then each function can be optimized, but the device size and component count increase
Solution Approach 1:
The scanning projector is designed to perform multiple functions using the same core components. The beam scanner can be configured to scan visible wavelengths for display purposes and infrared wavelengths for time-of-flight ranging and environmental mapping. This multi-functional design maintains high performance for both display and sensing while avoiding the volume penalty of separate dedicated systems.
Solution Approach 2:
The system employs dynamic configuration of the scanning projector to switch between different operational modes. The same optical hardware can be dynamically allocated to display functions or environmental mapping functions based on real-time needs, allowing a single compact system to replace what would traditionally require multiple fixed-function devices. The beam scanner's scanning patterns and wavelengths are dynamically adjusted to serve different purposes.
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
Enables compact and comfortable wearable displays that provide immersive 3D experiences by efficiently combining image and ranging functions, reducing size and weight, and enhancing user interaction with real-time environmental awareness.
Implementation Method 1
A beam scanner includes a tiltable reflector configured for receiving and angularly scanning an image beam to obtain an image in angular domain and for receiving and angularly co-scanning a ranging beam
Implementation Method 2
A pupil-replicating lightguide is coupled to the beam scanner for conveying portions of the scanned image beam to an eyebox of the display
Implementation Method 3
A detector is configured for receiving a portion of the ranging beam reflected from an object
Data Source
AI summary
A wearable display device includes a light source, a beam scanner, a pupil-replicating lightguide, and a detector. The light source is configured to emit an image beam and a ranging beam. The beam scanner co-scans both beams. The image beam is used to form an image in angular domain for displaying to a user of the wearable display device, and a ranging beam is used to scan outside environment at the same time. Light reflected from objects in the outside environment is detected by the detector, and a 3D map of the outside environment is built using time-of-flight measurements of the reflected signal and/or triangulation. For triangulation measurements, the detector may include a digital camera.