Active Alignment System for Waveguide Displays
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Solution Overview
Problem
In head-mounted display systems, accurately aligning and compensating for discrepancies between visual signals presented to each eye is challenging, affecting the precise simulation of objects in a user's ambient environment.
Innovation Solution
The system employs a first and second waveguide, each with a diffraction optical element, and an optical multiplexer to combine and adjust the signals, using an optical sensor to detect and compensate for misalignments and color differences between the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate visual signals are presented to left and right eyes through separate waveguides, then depth of field and spatial position perception are improved, but alignment precision between the two signals deteriorates
Solution Approach 1:
The patent combines the optical paths of two separate waveguides by using an optical multiplexer to merge them into a single detection path. This allows the sensing system to detect alignment discrepancies between left and right eye signals while maintaining the benefits of separate signal presentation for depth perception.
Solution Approach 2:
The patent introduces an intermediary sensing system that includes an optical sensor and optical multiplexer to mediate between the separate waveguide outputs. This intermediary system detects alignment errors without interfering with the primary function of presenting separate visual signals to each eye.
2Manufacturing precision
If an optical sensing system is added to detect alignment between waveguide signals, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The optical sensor and multiplexer serve multiple functions: they detect alignment errors between waveguides, enable calibration of the display system, and can potentially detect other optical parameters. This multi-functionality justifies the added complexity by providing multiple benefits from a single sensing subsystem.
3Measurement precision
If test patterns are rendered to verify waveguide alignment, then measurement accuracy is improved, but productivity decreases due to additional calibration time
Solution Approach 1:
The patent performs alignment verification using test patterns during the manufacturing and calibration phase before the product is deployed. By conducting this verification beforehand, the system ensures accurate alignment is achieved during setup, preventing future alignment issues and reducing the need for re-calibration.
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 ensures accurate alignment and color balance of visual signals, enhancing the realism of virtual and augmented reality experiences by improving the alignment and presentation of visual information.
Implementation Method 1
a first waveguide configured to guide a first signal, a second waveguide configured to guide a second signal
Implementation Method 2
each with a diffraction optical element
Data Source
AI summary
A display system includes a display alignment tracker configured track the position of a first signal and the position of a second signal. The display alignment tracker optically multiplexes a portion of a first signal and a portion of the second signal into a combined optical signal and measures a differential between the first signal and the second signal.