Rearward-Facing Sensor Integration Through Negative Bias Lenses
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Solution Overview
Problem
Existing head-mounted devices face challenges in integrating gaze tracking cameras without increasing bulkiness and compromising user comfort, especially when these cameras need to monitor the user's eyes through lenses that also display augmented reality images.
Innovation Solution
The integration of a negative bias lens with a protruding portion for mounting gaze tracking cameras on the outward surface, allowing the cameras to operate through the lens while maintaining a compact device size and user comfort, combined with a waveguide system for image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gaze tracking camera is integrated into the head-mounted device to monitor the user's eyes, then gaze tracking functionality is achieved, but the device becomes bulkier and less comfortable for the user
Solution Approach 1:
The patent combines the gaze tracking camera with the existing lens assembly by mounting the camera on the outward surface of the lens. This integration allows the camera to share the same structural space as the lens, eliminating the need for separate mounting structures and reducing overall device volume while maintaining gaze tracking functionality.
Solution Approach 2:
The lens assembly serves dual purposes: it functions as an optical element for displaying augmented reality images and simultaneously provides a mounting surface for the gaze tracking camera. This multi-functionality reduces the need for additional components and space, thereby reducing device bulkiness.
2Volume of moving object
If the gaze tracking camera is mounted on the outward surface of the lens, then the device remains compact, but the camera must operate through the lens which may affect optical performance
Solution Approach 1:
The patent applies local quality by creating a protruding portion on the lens surface that provides a dedicated mounting area for the camera. This localized modification allows the camera to be mounted without affecting the overall optical quality of the lens, as the protrusion is designed to minimize interference with light paths for both AR display and eye tracking.
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 effective gaze tracking without enlarging the device's overall size, ensuring user comfort and maintaining focus on both real-world and augmented reality images, while adhering to privacy and regulatory standards.
Implementation Method 1
Waveguides may be used to present the display images to eye boxes for viewing by a user
Implementation Method 2
The negative bias lens element may have a protruding portion through which the sensor operates, may have a surface facing the sensor that has a curved surface shape to provide a lens characteristic
Data Source
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AI summary
A head-mounted device (10) may have a housing (12) with a frame (12F) that supports lenses. Each lens may have a positive bias lens element and a negative bias lens element (16N). A waveguide may overlap the lens. During operation, images from the waveguide may be provided to an eye box (20) through the negative bias lens element. An eye sensor such as a gaze tracking camera (32) may operate through the negative bias lens element (16N). The negative bias lens element may have a protruding portion (38) through which the sensor operates, may have a surface (36) facing the sensor that has a curved surface to provide a desired lens characteristic, may have a prism (40) for helping to couple light from the eye box (20) to the eye sensor, and/or may have other features to facilitate use of the eye sensor to monitor the eye of a user in the eye box (20).