Pellicle Beamsplitter for HMD Eye Tracking Weight Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional head-mounted displays (HMDs) with eye tracking subsystems face challenges in minimizing their size and weight, as the placement and design of eye tracking components often increase the form factor and weight, compromising user comfort.
Innovation Solution
A pellicle beamsplitter is used to separate optical paths for eye tracking and display content in HMDs, positioned between the optics assembly and electronic display, with a deformable design that includes supports and transparent sheets to form curvature, allowing for efficient light transmission and reflection, thereby reducing the overall size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional eye tracking components are placed in HMDs to separate optical paths, then eye tracking functionality is achieved, but the form factor and weight of the HMD increase
Solution Approach 1:
The patent combines the eye tracking optical path separation function with the existing display optical path by positioning the pellicle beamsplitter between the optics assembly and electronic display. This integration allows the same optical component to serve dual purposes: directing display content to the user's eye while simultaneously directing reflected light from the eye to the eye tracking camera, thereby achieving eye tracking functionality without adding separate bulk components that would increase weight.
Solution Approach 2:
The patent employs a pellicle beamsplitter, which is a thin film structure, to separate optical paths for eye tracking and display content. This thin film approach replaces conventional bulky beam splitters or separate optical components, significantly reducing the weight and form factor of the HMD while maintaining the necessary optical path separation functionality.
2Reliability
If conventional eye tracking components are placed in HMDs to separate optical paths, then eye tracking functionality is achieved, but the form factor of the HMD increases
Solution Approach 1:
The patent combines the eye tracking optical path separation function with the existing display optical path by positioning the pellicle beamsplitter between the optics assembly and electronic display. This integration allows the same optical component to serve dual purposes: directing display content to the user's eye while simultaneously directing reflected light from the eye to the eye tracking camera, thereby achieving eye tracking functionality without adding separate bulk components that would increase volume.
Solution Approach 2:
The patent employs a pellicle beamsplitter, which is a thin film structure, to separate optical paths for eye tracking and display content. This thin film approach replaces conventional bulky beam splitters or separate optical components, significantly reducing the volume and form factor of the HMD while maintaining the necessary optical path separation functionality.
3Use of energy by moving object
If a pellicle beamsplitter is used to separate optical paths, then light transmission and reflection efficiency is improved, but device complexity increases
Solution Approach 1:
The patent uses a pellicle beamsplitter in the form of a thin film to achieve efficient light transmission and reflection. The thin film structure provides sufficient optical path separation while maintaining high transmission efficiency for display content and adequate reflection efficiency for eye tracking. This approach avoids the need for complex multi-component optical systems, thereby reducing device complexity while preserving optical efficiency.
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
The pellicle beamsplitter effectively separates light bands for eye tracking and display content, reducing the form factor and weight of HMDs while maintaining high transmission and reflectivity, enhancing user comfort and performance.
Implementation Method 1
a pellicle beamsplitter configured to redirect light in a second band reflected from the eye box toward the eye tracking unit and transmit the image light in the first band
Data Source
AI summary
A head-mounted display includes an electronic display configured to output image light, an optics assembly configured to direct image light in a first band from the electronic display to an eye box, an eye tracking unit configured to generate eye tracking information, and a pellicle beamsplitter configured to redirect light in a second band reflected from the eye box toward the eye tracking unit and transmit the image light in the first band. The pellicle beamsplitter is positioned along the optical axis between the optics assembly and the electronic display. The pellicle beamsplitter includes a front surface and a back surface. Each of the front surface and the back surface comprising a first radius curvature in a first plane and a second radius curvature in a second plane that is perpendicular to the first plane.