VR Headset Eye Tracking via Inter-Panel Camera Placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional virtual and mixed reality head-mounted displays (HMDs) face challenges in accurately tracking eye positions and movements due to keystone distortion and limited field of view, which affects gaze-based interactions and image quality.
Innovation Solution
The implementation of a head-mounted display with optical prisms and polarizing filters, along with near-IR eye tracking cameras located between display panels and off-center to minimize keystone distortion, allows for precise eye tracking and improved image projection, forming virtual images one to two meters in front of the user's eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eye tracking cameras are positioned in conventional HMD configurations, then the system structure is simplified, but keystone distortion occurs and measurement precision deteriorates
Solution Approach 1:
The patent positions eye tracking cameras in a different spatial dimension relative to the display panels - specifically, the cameras are located between the display panels rather than on the periphery. This dimensional repositioning allows the cameras to capture eye images without keystone distortion while maintaining system compactness.
Solution Approach 2:
The patent employs asymmetric positioning of the eye tracking cameras relative to the optical axis, with cameras offset to specific locations between the display panels. This asymmetric arrangement optimizes the viewing angle and eliminates distortion while keeping the overall structure balanced.
2Area of stationary object
If optical prisms are used to form virtual images, then field of view is improved, but device complexity increases
Solution Approach 1:
The optical prisms in the patent serve multiple functions simultaneously: they form virtual images at the desired distance, expand the field of view, and provide a clear optical path for the eye tracking cameras. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The patent integrates the eye tracking camera system with the existing optical prism structure, combining the image display function and eye tracking function into a unified optical path. The cameras utilize the same prism structure that forms the virtual image, eliminating the need for separate tracking optics.
3Illumination intensity
If polarizing filters are implemented for 3D display, then image quality is improved, but light transmission is reduced
Solution Approach 1:
The patent applies polarizing filters selectively to specific regions of the display system - placing them in front of the display panels where they are needed for 3D image separation. This localized application maintains image quality while minimizing overall light transmission loss.
Solution Approach 2:
The patent optimizes the polarizing filter parameters, including the polarization angle and material properties, to maximize light transmission while maintaining effective 3D image separation. By adjusting these parameters, the system achieves both high image quality and efficient light utilization.
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 configuration reduces keystone distortion, provides a wider field of view, and enables accurate gaze-based interactions and eye image animations, enhancing the user experience in virtual and mixed reality applications.
Implementation Method 1
Light from the top display panel passes through the P-polarizing filter and the P-polarized light passes through the first surface of the eyepiece, which is P-transmissive. The P-polarized light strikes the third surface of the eyepiece at an angle so that the light is reflected off the third surface by total internal reflection to the second surface of the eyepiece.
Implementation Method 2
P-polarized light has an electric field direction parallel to the plane of incidence on a surface, and S-polarized light has the electric field oriented perpendicular to that plane.
Data Source
AI summary
An apparatus for image viewing and eye tracking in virtual or mixed reality systems that includes two or more display panels (e.g., a top display panel and a bottom display panel) for each eye with left and right prisms located between the display panels and the user's eyes. S- and P-polarizing filters are located between the display panels and first and second surfaces of the prism. For each eye, the polarized light from the top and bottom display panels is redirected by a respective prism to form exit pupils for top and bottom images at a plane at or near the eye. At least one eye-tracking camera is located in front of each prism and between the top and bottom display panels so that the cameras have a direct or near-direct view of the user's eyes through the eyepieces.