Active Shutter Transparent Display for AR Privacy
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Solution Overview
Problem
Current augmented reality (AR) devices leak a portion of projected images, compromising the privacy of the wearer as observers outside can see the images, which is not addressed effectively by existing technologies.
Innovation Solution
An optical system comprising a transparent display, an image generator, and a shutter that alternates between blocking and transmitting states synchronized with image projection intervals, preventing image leakage during image generation and allowing scene visibility during blanking intervals, using a controller to manage these states based on ambient illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transparent display is used to project images into the eye while allowing external scene visibility, then the wearer can see merged images and scenes, but image leakage occurs allowing outside observers to see the projected images
Solution Approach 1:
The patent applies periodic action by synchronizing the shutter with the display to open and close at regular intervals. The shutter closes during image projection to block leakage and opens during blanking intervals to maintain scene visibility, creating a periodic cycle that resolves the contradiction between preventing image leakage and maintaining transparent display functionality
Solution Approach 2:
The patent implements preliminary action by closing the shutter before image projection begins and opening it after the projection cycle completes. This anticipatory timing ensures that the shutter is already in the correct state to prevent leakage at the start of each display cycle, eliminating image leakage before it can occur
2Object-generated harmful factors
If a shutter is added to block image leakage, then privacy is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical shutters with an electro-optic shutter using liquid crystals or similar materials. This substitution eliminates moving parts and mechanical complexity while maintaining the blocking function, reducing device complexity while still preventing image leakage effectively
Solution Approach 2:
The patent changes the optical parameters of the shutter material dynamically by applying electrical signals to alter the transparency state. This allows the shutter to transition between blocking and transparent states without mechanical movement, simplifying the device structure while achieving the required privacy protection
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
Prevents image leakage from AR devices to outside observers while allowing the wearer to see merged images and scenes, enhancing privacy and maintaining clear visibility of the external scene.
Implementation Method 1
the shutter includes a liquid crystal (LC) device
Data Source
AI summary
An optical system includes a transparent display, which has a first side configured to be positioned in proximity to an eye of an observer and a second side opposite the first side, and which is configured to project an image into the eye. An image generator is configured to generate a sequence of images during respective display intervals, which are interleaved with blanking intervals, and to transmit the images to the transparent display for projection into the eye. A shutter is positioned on the second side of the display and having a first state in which the shutter blocks optical radiation and a second state in which the shutter transmits optical radiation. A controller drives the image generator and the shutter so that the shutter operates in the first state during the display intervals and in the second state during the blanking intervals.