Zero Holding Power Piezoelectric Actuators for Head-Mounted Device Alignment
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Solution Overview
Problem
Head-mounted devices face optical component misalignment issues due to stress and deformation, leading to image distortion, which existing technologies fail to adequately correct without consuming excessive power.
Innovation Solution
Incorporating sensor circuitry to detect misalignment and control circuitry to adjust the positions of optical components using zero holding power piezoelectric actuators, ensuring accurate alignment of projectors, waveguides, and prisms to prevent distortion while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional actuators are used to correct optical misalignment, then alignment accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic alignment correction by using sensors to detect misalignment and activating actuators only when correction is needed, rather than continuous operation. The system periodically checks alignment status and applies corrections only when misalignment exceeds thresholds, reducing overall power consumption while maintaining alignment accuracy.
Solution Approach 2:
The patent replaces traditional continuous-power mechanical actuators with zero-holding-power piezoelectric actuators. These piezoelectric devices convert electrical energy directly to mechanical displacement only when voltage is applied, and maintain position without power consumption when voltage is removed, thus achieving high precision alignment correction with minimal power usage.
2Reliability
If optical components are made adjustable to correct misalignment, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent divides the optical system into separable components (projectors, waveguides, prisms) that can be independently adjusted. Each optical component has its own positioning mechanism controlled by dedicated actuators, allowing precise alignment correction without requiring complex integrated adjustments of the entire optical system.
Solution Approach 2:
The patent implements feedback control by using sensors to continuously monitor optical component alignment and feeding this information back to control circuitry. The control system processes sensor data and generates actuator commands to maintain proper alignment, creating a closed-loop system that automatically compensates for misalignment while managing complexity through intelligent control.
3Measurement precision
If sensors continuously monitor misalignment, then alignment precision is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring by having sensors check alignment at specific intervals or triggered by events (such as device movement detection or user interaction), rather than continuous real-time monitoring. This approach maintains sufficient alignment precision for normal operation while dramatically reducing power consumption during steady-state operation.
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
Effectively corrects optical misalignment and prevents image distortion in head-mounted devices, conserving power by only consuming energy during repositioning, thus maintaining clear and undistorted images for the user.
Implementation Method 1
zero hold power piezoelectric actuators configured to adjust optical alignment of the projector, waveguide, and prism
Implementation Method 2
The waveguides may be used in conveying the images from the projectors to the eye boxes
Implementation Method 3
Optical couplers such as prisms may be used to couple images from the projectors into the waveguides
Data Source
AI summary
A head-mounted device may have display projectors that provide images. Waveguides may be used in conveying the images to eye boxes. Optical couplers such as prisms may be used to couple the images from the projectors into the waveguides. The waveguides may guide the images to output couplers that couple the images toward eye boxes for viewing by a user. During operation of the head-mounted device, sensor circuitry may be used to measure for potential misalignment between optical components such as projectors, couplers, and waveguides. Control circuitry may provide control commands to zero hold power piezoelectric actuators or other positioners based on the sensor measurements, thereby tilting and otherwise repositioning the optical components relative to each other to correct for optical component misalignment.