Coupling Prism Optical Multiplexing for HMD Imaging
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Solution Overview
Problem
Conventional HMDs require multiple imaging sensors to capture multiple views, leading to increased manufacturing costs, power consumption, and inter-channel interference (ICI), while failing to support 3D reconstruction of biometric features and image displaying simultaneously.
Innovation Solution
An apparatus using a coupling prism with multiple DR prisms to optically multiplex single-channel images into a multi-channel image, allowing a single imaging sensor to capture multiple views while minimizing ICI, and incorporating a micro display for image displaying functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple imaging sensors are installed to capture multiple views, then the number of views for imaging is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple imaging functions (internal sensing and external sensing) into a single imaging sensor by using an optical arrangement with a convex reflective mirror. This allows one sensor to capture both eye views and scene views that would traditionally require separate sensors, thereby reducing manufacturing cost while maintaining multi-view imaging capability.
Solution Approach 2:
The single imaging sensor is designed to perform multiple functions: capturing internal sensing views (eye reflections) and external sensing views (surrounding scene) simultaneously. This multi-functional approach eliminates the need for dedicated sensors for each function, reducing overall system cost and complexity.
2Adaptability or versatility
If multiple imaging sensors are installed to capture multiple views, then the number of views for imaging is improved, but the device weight increases
Solution Approach 1:
The patent combines multiple imaging functions into a single sensor system, eliminating the weight of additional sensors, mounting structures, and associated electronics. The optical arrangement uses reflective surfaces to redirect light paths, allowing one lightweight sensor to perform work that would traditionally require multiple heavier components.
3Adaptability or versatility
If multiple imaging sensors are installed to capture multiple views, then the number of views for imaging is improved, but the power consumption increases
Solution Approach 1:
The patent consolidates multiple imaging operations into a single sensor, reducing power consumption by eliminating redundant sensor operations, data processing loads, and electronic overhead associated with multiple independent sensing systems.
4Ease of manufacture
If a convex reflective mirror is used to multiplex eye view and scene view onto a single imaging sensor, then the number of sensors is reduced, but inter-channel interference occurs
Solution Approach 1:
The patent extracts and removes the harmful element (convex reflective mirror) that causes inter-channel interference. Instead of using a multiplexing approach that combines light paths, the invention employs separate optical paths with beam splitters and mirrors that direct different views to the sensor at different times or through different channels, eliminating the interference problem while still using a single sensor.
5Ease of manufacture
If a single imaging sensor is used to reduce manufacturing cost, then the manufacturing cost is reduced, but the ability to support 3D reconstruction of biometric features is lost
Solution Approach 1:
The patent performs preliminary actions by capturing multiple views of the eye from different angles using the single imaging sensor and optical arrangement. These pre-captured multi-angle images are then processed through 3D reconstruction algorithms to generate three-dimensional biometric features, enabling 3D reconstruction capability without requiring multiple simultaneous sensors.
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 efficient imaging of multiple views with reduced ICI, supports 3D reconstruction, and integrates sensing and image displaying capabilities, reducing the number of sensors needed and enhancing user interaction.
Implementation Method 1
The individual DR prism comprises an internal diagonal plane at least partially reflective for reflecting a respective single-channel image received through an image-receiving end surface of the individual DR prism towards an image-leaving end surface
Implementation Method 2
The imaging sensor overlies the substantially flat surface for imaging the multi-channel image upon the multi-channel image exiting the coupling prism
Data Source
AI summary
An apparatus installed in a head-mounted display (HMD) has a coupling prism formed by packing diagonally-reflective (DR) prisms together. Each DR prism has an internal diagonal plane that is at least partially reflective. A captured image of eye or environmental scene received by a DR prism is reflected to an image-leaving end surface thereof. Image-leaving end surfaces of all DR prisms are oriented along a same direction to optically multiplex the captured images to create a multi-channel image. An imaging sensor on the coupling prism images the multi-channel image, avoiding inter-channel interference caused by spillover of captured-image signals while allowing one imaging sensor instead of multiple ones to image the captured images. A micro display displays a visible image to one DR prism, whose internal diagonal plane reflects the visible image along a direction towards an eye. Hence, the apparatus also enables image displaying to a HMD wearer.