Varifocal HMD with Modular Air-Spaced Optical Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Head-mounted displays (HMDs) face challenges in accommodating varying optical prescriptions, leading to distortion and focus errors, particularly when users wear unknown or third-party optical elements, which can cause discomfort and affect the accuracy of eye tracking systems.
Innovation Solution
A varifocal system integrated into HMDs, featuring a modular air-spaced optical assembly with a front and back optical element, allows for dynamic focus adjustment based on eye tracking information and optical correction, enabling users to customize the focus for their prescription without needing external glasses, and compensates for astigmatism through rotatable and replaceable optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If users wear third-party optical elements or prescription glasses within the HMD, then optical correction is provided, but distortion and focal errors are introduced
Solution Approach 1:
The patent extracts the optical correction function from external glasses or third-party elements and integrates it directly into the HMD optical path. The HMD includes built-in optical elements (lenses or prism assemblies) that can be configured to provide prescription-specific optical correction, eliminating the need for users to wear external corrective elements that would introduce distortion and focal errors.
Solution Approach 2:
The optical correction system is segmented into multiple adjustable components within the HMD, including replaceable optical elements and adjustable optical paths. This allows the system to be configured for different prescriptions while maintaining image quality, as each segment can be optimized independently rather than relying on a single fixed optical element.
2Adaptability or versatility
If optical elements are added to correct prescription, then vision correction is achieved, but device complexity increases
Solution Approach 1:
The HMD optical assembly is designed with universal, multi-functional optical elements that can serve multiple purposes: providing optical correction for various prescriptions, maintaining proper focus, and enabling eye tracking functionality. The optical elements are configured to work across different prescription ranges, reducing the need for numerous specialized components.
Solution Approach 2:
The optical assembly incorporates dynamic adjustment capabilities, allowing optical elements to be repositioned or replaced based on the user's prescription. The system can dynamically adjust focal length, optical path length, or element positioning to accommodate different prescriptions, rather than requiring fixed, prescription-specific hardware configurations.
3Ease of operation
If focus adjustment is added to accommodate prescriptions, then visual comfort is improved, but device complexity increases
Solution Approach 1:
The HMD incorporates self-service focus adjustment mechanisms that automatically adapt to the user's prescription without requiring manual intervention. The system uses eye tracking data and optical sensors to automatically adjust focal length and optical path configuration, providing visual comfort through automated adaptation rather than complex manual adjustment mechanisms.
Solution Approach 2:
The optical system incorporates feedback loops that use eye tracking information and optical sensor data to continuously monitor and adjust focus settings. The system receives feedback on the user's visual state and automatically adjusts optical parameters to maintain optimal focus and comfort, reducing the need for complex manual control mechanisms.
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 system ensures clear image presentation for users with varying prescriptions, mitigates vergence-accommodation conflict, and enhances user comfort by providing accurate optical correction and improved eye tracking performance.
Implementation Method 1
The back optical element is configured to receive the image light from the electronic display... the front optical element receives light transmitted by the back optical element
Data Source
AI summary
A head-mounted display (HMD) includes an electronic display configured to emit image light, an optical assembly that provides optical correction to the image light, an eye tracking system, and a varifocal module. The optical assembly includes a back optical element configured to receive the image light from the electronic display, and a coupling assembly configured to couple a front optical element to a location within the optical assembly such that the front optical element receives light transmitted by the back optical element. The optical correction is determined in part by an optical characteristic of the front optical element that is replaceable. The eye tracking system determines eye tracking information for a first eye of a user of the HMD. A varifocal module adjusts focus of images displayed on the electronic display, based on the eye tracking information and the optical correction.