Augmented Reality HMD Shutter for Fail-Safe Direct View
Solution Overview
Problem
Head-mounted displays (HMDs) used for augmented reality can malfunction, causing the user to lose the ability to see the real-world environment when the display or outward-facing imaging sensor fails, necessitating a fail-safe mode to ensure continued visibility.
Innovation Solution
The HMD incorporates an electrically switchable shutter that remains closed during normal operation to enhance image contrast but opens when the display or imaging sensor fails, allowing direct viewing of the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the shutter is closed to block ambient light and enhance image contrast, then image quality is improved, but the user loses direct visibility of the environment when the display or imaging sensor fails
Solution Approach 1:
The shutter is designed to be electrically switchable between closed and open states, allowing it to dynamically adapt its position based on system operational status. During normal operation, the shutter remains closed to enhance image contrast by blocking ambient light. When display or imaging sensor failure is detected, the shutter automatically opens to provide direct environmental visibility, thus resolving the contradiction between image quality and visibility reliability.
2Reliability
If the shutter is opened to provide direct view of the environment, then visibility reliability is improved, but image contrast and quality deteriorate
Solution Approach 1:
The shutter's electrically switchable design enables it to transition between open and closed states based on real-time system monitoring. When the system detects proper operation of the display and imaging sensor, the shutter closes to maximize image contrast. Upon detecting failure conditions, the shutter opens to ensure continuous visibility, thus dynamically resolving the trade-off between visibility reliability and image contrast.
3Reliability
If the system continuously monitors for failures to maintain fail-safe mode, then visibility reliability is improved, but device complexity increases
Solution Approach 1:
The system incorporates monitoring circuitry that continuously detects the operational status of the display and imaging sensor components. This feedback mechanism triggers automatic shutter response: when failures are detected, the monitoring system activates the fail-safe mode by opening the shutter. This feedback-based approach ensures high visibility reliability while keeping the monitoring system relatively simple and integrated within the existing HMD architecture.
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
Ensures continued user visibility and enhanced image contrast by providing a direct view of the environment when the display or imaging sensor malfunctions, maintaining functionality even in failure scenarios.
Implementation Method 1
an electrically switchable shutter having a closed state that blocks light
Implementation Method 2
a beam combiner that is partially reflective and partially transmissive
Implementation Method 3
a beam combiner that is partially reflective and partially transmissive
Data Source
AI summary
Various AR systems include a fail-safe mode where the user can see the region in front of the user without the display and/or outward facing imaging sensor (e.g., camera), if for example, power to the display and/or outward facing imaging sensor (e.g., camera) is lost or the outward facing imaging sensor (e.g., camera) and/or display malfunction.