Fiber Scanning Projector Position Detection Using Characterization Light
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing augmented reality systems lack efficient methods for accurately determining the position of light projection from scanning cantilevers, which is crucial for producing undistorted images in wearable displays.
Innovation Solution
The system uses a scanning cantilever with a cantilever position detection system that incorporates a dichroic mirror or dichroic polarizing beam splitter to separate display light and characterization light, allowing for precise measurement of the cantilever's position using a quadrant detector or photodiode, enabling real-time feedback for image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a scanning cantilever is used to project light in augmented reality systems, then the display can be made compact and wearable, but the position of light projection becomes difficult to detect accurately
Solution Approach 1:
The patent introduces characterization light as an intermediary signal that does not interfere with display light but carries position information. This characterization light is coupled into the scanning fiber and emerges at the distal end to indicate fiber position, enabling accurate detection without adding bulk to the wearable display system.
Solution Approach 2:
The patent replaces direct mechanical position sensing with an optical-based characterization light detection system. By using optical detectors to sense the position of characterization light, the system achieves precise position measurement without complex mechanical sensors attached to the scanning cantilever.
2Ease of operation
If display light is used alone in the scanning fiber, then the augmented reality image can be projected, but the position of the scanning fiber cannot be determined
Solution Approach 1:
The scanning fiber serves dual functions: projecting display light for augmented reality imaging and transmitting characterization light for position detection. This multi-functionality allows the same optical path to provide both image projection and position information without requiring separate systems.
Solution Approach 2:
The patent utilizes different wavelength parameters to distinguish between display light and characterization light. By assigning characterization light to a specific wavelength band distinct from the visible display light, the system can simultaneously perform image projection and position sensing without interference.
3Measurement precision
If additional characterization light is added to detect fiber position, then position detection becomes possible, but the system complexity and cost increase
Solution Approach 1:
The patent uses a dichroic mirror as an intermediary optical element that selectively reflects characterization light while transmitting display light. This allows position detection optics to be integrated into the existing display system without requiring complete optical path separation, thereby limiting the increase in system complexity.
4Reliability
If real-time position feedback is implemented, then image stabilization is improved, but the system requires more complex detection and feedback mechanisms
Solution Approach 1:
The patent implements a feedback loop where the position of characterization light is detected in real-time and used to determine scanning fiber position. This position information feeds back to the control system to stabilize the augmented reality image, improving reliability through continuous correction.
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
This approach enables real-time or near-real-time detection of the optical waveguide's position, providing accurate feedback for image stabilization and maintaining image quality in wearable displays, while being compact and cost-effective.
Implementation Method 1
an optical assembly section including a dichroic mirror operable to reflect at least a portion of the display light and transmit at least a portion of the characterization light
Implementation Method 2
a position measurement device operable to receive the transmitted portion of the characterization light
Data Source
AI summary
A projector including a cantilever position detection system includes a chassis and an actuator mounted to the chassis. The projector also includes a cantilever light source having a longitudinal axis and mechanically coupled to the actuator. The cantilever light source is operable to transmit display light and characterization light. The projector further includes an optical assembly section operable to receive the display light and the characterization light. The optical assembly section includes a dichroic mirror operable to reflect at least a portion of the display light and transmit at least a portion of the characterization light. Moreover, the projector includes a position measurement device operable to receive the transmitted portion of the characterization light.