Steered Eyebox Near-Eye Display Using Tiltable MEMS Mirror
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Solution Overview
Problem
Current eye-tracking systems in near-eye displays, such as head-mounted displays (HMDs), face challenges in efficiently steering virtual images to match the pupil position, leading to reduced resolution and increased power consumption due to the need to present images to a full eyebox without precise tracking.
Innovation Solution
A near-eye optical system incorporating a lightguide, a tiltable reflector, and an infrared light source, which steers both visible and infrared light beams to a smaller eyebox region using a MEMS tiltable mirror, allowing the eye-tracking sensor to generate a tracking signal and adjust the reflector's position to align the eyebox with the pupil, thereby improving image resolution and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full eyebox is used to present virtual images without precise eye-tracking, then the system maintains broader viewing coverage, but image resolution decreases and power consumption increases
Solution Approach 1:
The patent implements a dynamic eyebox that can be steered to different positions using a tiltable reflector (MEMS mirror) based on detected pupil position. Instead of maintaining a static full eyebox, the system dynamically adjusts the eyebox position to match the user's actual pupil location, enabling precise tracking while reducing the active display area and associated power consumption
Solution Approach 2:
The patent applies local quality by concentrating the virtual image presentation to a localized steered eyebox region rather than distributing it across the full eyebox. This allows high-resolution rendering to be focused only on the area where the user's pupil is actually located, improving effective resolution while reducing the computational and power resources needed to render the entire full eyebox
2Measurement precision
If a full eyebox is used to present virtual images without precise eye-tracking, then the system maintains broader viewing coverage, but image resolution decreases
Solution Approach 1:
The system dynamically steers the eyebox to precisely align with the user's pupil position using a MEMS tiltable reflector. This dynamic adjustment ensures that the high-resolution virtual image is always presented at the correct location, maintaining manufacturing precision and image quality even when the user's eye moves within the field of view
Solution Approach 2:
By concentrating the high-resolution virtual image rendering to a smaller steered eyebox region that matches the actual pupil location, the system achieves better effective resolution. The local quality principle allows the display resources to be focused on the relevant area rather than diluting resolution across the entire full eyebox
3Adaptability or versatility
If separate optical paths are used for visible light and infrared illumination, then the system achieves independent control of each wavelength, but device complexity increases
Solution Approach 1:
The patent merges the optical paths for visible light and infrared illumination by using a single tiltable reflector (MEMS mirror) to steer both wavelengths. The infrared illumination light and visible light beams share the same optical components and steering mechanism, reducing device complexity while maintaining the ability to independently control each wavelength through separate light sources and detectors
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 enables higher resolution virtual images by precisely steering them to the pupil location, reducing power consumption and enhancing the overall viewing experience by utilizing eye-tracking to adjust the eyebox position, applicable in VR, AR, and MR HMDs.
Implementation Method 1
The tiltable reflector receives visible light beams and infrared illumination light and directs the visible light beams and the infrared illumination light to an eyebox region
Implementation Method 2
The sensor receives returning infrared light, which is the infrared illumination light reflecting or scattering from the eyebox region
Data Source
AI summary
Illumination light is emitted from a light source. The illumination light is directed to an eyebox region via a lightguide. Illumination light and visible light beams are incoupled into the lightguide by a tiltable reflector. A tracking signal is generated with a sensor in response to a returning light becoming incident on the sensor.