Beam Steering Mechanism for Wide Field of View HMDs
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Solution Overview
Problem
Conventional Head Mounted Displays (HMDs) face challenges in providing a wide field of view (FOV) without increasing the size and cost of the headset, as well as managing power consumption, due to the need for larger display sizes and optics, which results in bulky and power-hungry devices.
Innovation Solution
The implementation of a Beam Steering Mechanism (BSM) within the display projection module allows for dynamic steering of the FOV in one, two, or three dimensions, using electrically actuated switches to steer the projected image towards different portions of the lens, enabling a wider effective FOV without increasing the physical size of the display, and utilizing high-speed technologies like DLP MEMS micro-displays to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the display size is increased to provide Wide FOV, then the FOV is improved, but the headset size and weight increase significantly
Solution Approach 1:
The patent applies dynamic beam steering using a scanning mirror that rapidly redirects light beams across the lens aperture. Instead of a static large display, the system dynamically sweeps a small display's output across different angles, creating a time-averaged wide FOV. The scanning mirror changes orientation continuously during each frame cycle, steering light to different portions of the lens to synthesize an expanded viewing angle.
Solution Approach 2:
The system uses periodic scanning at high frequency (e.g., 60Hz or higher) where the beam steering mechanism repeatedly sweeps across the FOV within each display frame. This periodic action creates the perception of a continuous wide FOV through persistence of vision, while the physical display remains small. The scanning rate is synchronized with the display refresh rate to maintain image stability.
2Illumination intensity
If the display size is increased to provide Wide FOV, then the FOV is improved, but the power consumption increases
Solution Approach 1:
The patent employs dynamic beam steering with a small display and scanning mirror to achieve wide FOV. The small display consumes significantly less power than a large display would require, while the scanning mechanism uses minimal energy compared to the power savings from using a compact display. The system dynamically redirects light rather than physically expanding the display area, maintaining low power consumption.
Solution Approach 2:
The patent replaces the mechanical approach of using a large physical display with an optical-mechanical system combining a small display and beam steering. Instead of increasing display size to expand FOV, the system substitutes a scanning mechanism that redirects light angularly, achieving the same effect with much lower power requirements.
3Illumination intensity
If the optics size is increased to collect light from larger display, then the FOV is improved, but the headset size increases
Solution Approach 1:
The patent uses dynamic beam steering to redirect light from a small display through a fixed-size lens aperture. The scanning mirror dynamically angles the light beam to sweep across the aperture, creating a time-averaged wide FOV without requiring a physically large lens. The optics size remains compact while the effective FOV is expanded through angular scanning.
Solution Approach 2:
The system employs periodic beam scanning where the steering mechanism rapidly redirects light across the lens aperture at high frequency. This periodic angular modulation creates the perception of a wide FOV through persistence of vision, while the physical lens aperture remains small. The scanning action synthesizes an expanded angular field without increasing optical component sizes.
4Illumination intensity
If a Beam Steering Mechanism is used to dynamically steer FOV, then the effective FOV is widened, but the device complexity increases
Solution Approach 1:
The patent integrates the beam steering mechanism within the existing display projection module, making the scanning mirror serve multiple functions: expanding FOV, maintaining compact form factor, and enabling dynamic control of light direction. The controller that drives the display also synchronizes the scanning mirror, consolidating control functions and reducing overall system complexity despite adding beam steering capability.
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 approach allows for an effectively wider FOV that is indistinguishable to the human observer, while significantly reducing power consumption by dynamic on-demand steering, thus maintaining practicality and efficiency in HMD applications.
Implementation Method 1
A combiner optic receives the steered beam of light and redirects the steered beam of light to a viewer's eye
Implementation Method 2
The pupil forming optics transform the image from image space to angular space by collimating the diverging rays into collimated beams
Data Source
AI summary
A head mounted display with wide field of view (WFOV) is disclosed. A conventional small display is used in conjunction with a Beam Steering Mechanism (BSM) to dynamically steer the FOV of the displayed image at a very fast rate to provide an effectively WFOV for immersive visual experience. An electrically actuated switchable Steering Mechanism (SM) is provided within the display projection module that steers the projected image towards different portions of the lens at a fast rate. The steering can be either in one, two or three dimensions. The steering allows for the displayed image to be wider field of view (FOV) to the observer than conventionally projected images that are small fixed FOV. The SM is steered at a high rate so as to be indistinguishable to the human observer. The steering can be controlled in a gaze tracked dynamic, on-demand fashion so as to save power consumed by the display system.