Voice Coil Actuator Eye Tracking for HMD Image Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Head-Mounted Display (HMD) systems face challenges in accurately and efficiently translating optical components to match human eye movements, resulting in slow response times and inadequate precision, which negatively impacts the immersive experience in augmented, virtual, and mixed reality environments.
Innovation Solution
The implementation of voice coil actuators (VCAs) to translate projectors and optical elements within HMD systems, allowing for precise and fast movement in multiple directions, including perpendicular and parallel to major surfaces, while being constrained to prevent unwanted Z-direction movement, and the use of guidance systems to inhibit rotation and Z-direction translation, ensuring accurate pupil replication and image alignment with the user's eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional HMD systems use traditional actuation mechanisms to move optical components, then the system structure remains simple, but the response time is slow and precision is inadequate to match human eye movements
Solution Approach 1:
The patent replaces conventional mechanical actuation mechanisms with voice coil actuators that utilize electromagnetic fields to move optical components. This substitution enables faster response times and higher precision tracking of eye movements while maintaining a relatively compact system structure suitable for HMD applications.
Solution Approach 2:
The patent changes the actuation parameters by using voice coil actuators capable of high-speed, high-precision movement. The electromagnetic actuation system allows for rapid adjustment of optical component positions with fine control, matching the speed and precision requirements of human eye tracking without excessive mechanical complexity.
2Measurement precision
If voice coil actuators are used to translate optical components rapidly and precisely, then image alignment with user's eye is improved, but the system requires additional guidance mechanisms to constrain unwanted movement
Solution Approach 1:
The patent introduces guidance mechanisms as intermediary structures that work in conjunction with voice coil actuators. These guidance mechanisms provide physical constraints to prevent unwanted Z-direction translation and rotation of optical components, while allowing the voice coil actuators to achieve precise image alignment through controlled movement in permitted degrees of freedom.
3Adaptability or versatility
If the optical element and projector are translated to track eye movements, then the immersive experience is enhanced, but control over multiple degrees of freedom becomes complex
Solution Approach 1:
The patent segments the control system into distinct voice coil actuators, each responsible for specific degrees of freedom (X and Y directions). This segmentation allows independent control of different movement axes, simplifying the overall control architecture while achieving comprehensive eye tracking adaptability across multiple degrees of freedom.
Solution Approach 2:
The patent employs voice coil actuators that can function across multiple degrees of freedom, with each actuator capable of controlling movement in perpendicular directions. This multi-functionality reduces the total number of actuators needed while maintaining comprehensive eye tracking capability, thereby reducing control system complexity.
4Reliability
If translation of projector and optical element is constrained to prevent Z-direction movement, then image focus is maintained, but the guidance mechanism adds structural complexity
Solution Approach 1:
The patent implements dynamic constraints through guidance mechanisms that allow controlled movement in X and Y directions while maintaining stability in the Z-direction. The guidance structures provide flexible constraints that maintain image focus by preventing unwanted axial movement, while accommodating the dynamic positioning requirements of eye tracking through controlled lateral movement.
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 HMD systems to achieve sufficient speed and precision in moving displayed images to correspond with user eye movements, enhancing the immersive experience by maintaining image alignment and focus, thereby improving user engagement in artificial reality environments.
Implementation Method 1
The at least one voice coil actuator may be mounted on the HMD frame and may be coupled to the projector and/or optical element such that the at least one voice coil actuator, when actuated, may translate at least one of the projector or the optical element
Data Source
AI summary
The disclosed head-mounted display systems may include an optical element supported by a head-mounted display frame, a projector mounted to the head-mounted display frame, and at least one voice coil actuator mounted on the head-mounted display frame. The projector may be configured to project, via the optical element, an image toward an eye of a user of the head-mounted display system. The at least one voice coil actuator may be coupled to at least one of the projector or the optical element. When actuated, the at least one voice coil actuator may translate at least one of the projector or the optical element in at least one direction relative to the head-mounted display frame. Various other methods, systems, and methods of manufacture are also disclosed.