HMD Waveguide Optical System for Dual Projection
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) are limited by cost, size, weight, field of view, and efficiency, which restrict their practical and leisure applications in augmented reality and other fields.
Innovation Solution
The development of wearable glasses with integrated miniature projectors and cameras, along with advanced optics, allows for both private and public projection of computer-generated images, enabling user interaction and efficient display of content, including the ability to project virtual keyboards and other interactive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional optical systems are used in HMDs, then the basic display function is achieved, but the cost, size, weight, field of view, and efficiency are limited
Solution Approach 1:
The patent combines private projection optics and public projection optics into a single integrated optical system within the HMD. The private projector and public projector share common structural elements and optical paths where possible, reducing the overall number of components while maintaining both display functions simultaneously.
Solution Approach 2:
The optical system is designed to perform multiple functions: it can project images privately into the user's eye, project images publicly to external surfaces, and switch between these modes. The same HMD structure supports both augmented reality private viewing and public display capabilities.
2Adaptability or versatility
If separate projectors are used for private and public projection, then both functions are achieved, but the device size, weight, and cost increase
Solution Approach 1:
The patent merges the private projector and public projector into a single integrated unit. Both projection systems share common components including the optical engine, light source, and control electronics, eliminating the need for two completely separate projector systems and thereby reducing overall weight.
Solution Approach 2:
The projector system is designed as a multi-functional unit that can operate in private projection mode, public projection mode, or both simultaneously. This universal design allows one projection system to fulfill multiple roles that would traditionally require separate dedicated systems.
3Adaptability or versatility
If conventional HMD optical systems are used, then basic display is possible, but field of view and efficiency are restricted
Solution Approach 1:
The patent utilizes waveguide optics and total internal reflection to guide light through three-dimensional optical paths within the thin HMD structure. This allows the system to achieve a wide field of view by manipulating light in multiple spatial dimensions rather than relying on simple linear optical paths.
Solution Approach 2:
The system replaces traditional mechanical projection mechanisms with optical waveguides and photonic structures that can redirect and focus light efficiently. This substitution enables higher display efficiency and broader field of view without the mechanical constraints of conventional projection systems.
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 solution enhances the functionality and usability of HMDs by enabling private and public projections simultaneously, improving user interaction and efficiency, while potentially reducing costs and size through the use of a single projector for both purposes.
Implementation Method 1
a waveplate retarder, such as a half-wave plate, configured to manipulate a polarization orientation of the polarized CGI light
Implementation Method 2
a polarizing beam splitter configured to reflect the manipulated polarized CGI light along a first path when the manipulated polarized CGI light has a first polarization orientation and configured to pass the manipulated polarized CGI light along a second path when the manipulated polarized CGI light has a second polarization orientation
Data Source
AI summary
An apparatus includes an illumination module, an end reflector, and a beam splitter. The illumination module launches display light along a forward propagating path within an eyepiece. The end reflector is disposed at an opposite end of the eyepiece from the illumination module and reflects back the display light traveling along a reverse propagating path. The beam splitter is disposed in the forward propagating path between the end reflector and the illumination module. The beam splitter directs a first portion of the display light traveling along the forward propagating path out a first side of the eyepiece. The beam splitter directs a second portion of the display light traveling along the reverse propagation path out a second side of the eyepiece.