Head-Mounted Display Mirror System for Expanded Field of View
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) have a limited field of view (FOV) due to the impractical size and weight of lenses required to achieve larger FOVs, which restricts their application in virtual and augmented reality headsets.
Innovation Solution
Incorporating a mirror system with a primary and extended display, where the extended display's content is reflected onto the user's peripheral vision, increasing the FOV beyond the limitations of conventional lenses by using an aspherical mirror to direct light from the extended display to the exit pupil, thereby enhancing the overall viewing experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the diameter of conventional lenses is increased to increase FOV, then the FOV increases, but the weight and size of the lens become impractical for HMD applications
Solution Approach 1:
The display is segmented into a primary display for central vision and an extended display for peripheral vision. The primary display content is viewed through the lens while the extended display content is viewed through mirror reflections, allowing the system to achieve a larger effective FOV without requiring a single large-diameter lens for the entire FOV.
Solution Approach 2:
A mirror is introduced as an intermediary optical element to redirect light from the extended display to the user's eye. The mirror reflects light originating from the extended display and presents it at the exit pupil, enabling peripheral vision content to be delivered without requiring a large-diameter lens.
2Area of stationary object
If the diameter of conventional lenses is increased to increase FOV, then the FOV increases, but the lens becomes impractical for HMD applications
Solution Approach 1:
The display is segmented into a primary display for central vision and an extended display for peripheral vision. The primary display content is viewed through the lens while the extended display content is viewed through mirror reflections, allowing the system to achieve a larger effective FOV without requiring a single large-diameter lens for the entire FOV.
Solution Approach 2:
A mirror is introduced as an intermediary optical element to redirect light from the extended display to the user's eye. The mirror reflects light originating from the extended display and presents it at the exit pupil, enabling peripheral vision content to be delivered without requiring a large-diameter lens.
3Shape
If content on the extended display is reversed in both X and Y directions to correct mirror orientation, then the content orientation is corrected, but optical errors such as pincushion distortion are introduced
Solution Approach 1:
The content displayed on the extended display is pre-distorted before being sent to the mirror. This pre-distortion compensates for the distortion that will be introduced when the content is reversed and reflected by the mirror, ensuring that the final displayed content has the correct geometry and orientation without excessive optical errors.
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 effectively increases the FOV of HMDs beyond the conventional 110 degrees, approaching human vision's theoretical limit of 200 degrees per eye, while maintaining a compact and lightweight design, optimizing system resources, and correcting optical errors.
Implementation Method 1
The mirror is positioned between the exit pupil and the electronic display such that the mirror reflects light originating from the extended display and provides the reflected light to the exit pupil to increase the FOV
Data Source
AI summary
A head-mounted display (HMD) (e.g., VR headset or AR headset) displays a 3D virtual scene and includes a mirror to increase a field of view (FOV). The HMD includes an electronic display that further includes a primary display and an extended display, where the content displayed on the primary display is presented to the user's eye at an exit pupil through a lens and content displayed on the extended display is presented at the exit pupil through reflections of the mirror. The mirror is positioned between the exit pupil and the electronic display such that the mirror reflects light originating from the extended display and provides the reflected light to the exit pupil to increase the FOV. The combination of the content viewed through the lens and that of the reflected light of the extended display results in an FOV larger than when the content is viewed only through the lens.