Flexible Waveguide Mounting Structures for Drop Protection
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Solution Overview
Problem
Head-mounted devices are susceptible to deformation and damage of optical components such as waveguides due to excessive stress from forces applied during drop events or other situations.
Innovation Solution
The waveguides are mounted to the head-mounted frame using flexures that mechanically decouple them, comprising stacked rings forming springs to absorb impact and allow movement, with an elastomeric stress attenuator to absorb additional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If waveguides are rigidly mounted to the frame, then structural stability is improved, but the waveguides are susceptible to deformation and damage during drop events
Solution Approach 1:
The patent applies beforehand cushioning by introducing flexures with stacked rings that act as spring elements between the waveguide and frame. These rings are pre-configured to deform elastically during impact events, absorbing shock before it can reach the waveguide. The elastomeric material in the flexure provides additional cushioning, preventing waveguide deformation during drop events while maintaining structural stability during normal operation.
2Reliability
If waveguides are mechanically decoupled from the frame, then protection against impact is improved, but the mounting structure becomes more complex
Solution Approach 1:
The patent applies the nested doll principle by configuring the flexure with multiple rings stacked and coupled together, where each ring is coupled to adjacent rings at multiple locations to form spring elements. This nested arrangement of rings within the flexure structure provides multiple levels of mechanical decoupling and shock absorption while maintaining a compact form factor. The elastomeric material is integrated into the flexure assembly, combining multiple protective functions in a single component.
3Object-affected harmful factors
If flexures with stacked rings are used to mount waveguides, then impact absorption is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies composite materials by combining metal rings with elastomeric material in the flexure assembly. The metal rings provide structural integrity and elastic deformation capability, while the elastomeric material provides additional shock absorption and damping. This composite construction leverages the complementary properties of different materials to achieve superior impact absorption while maintaining manufacturability through established material processing techniques.
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
Prevents deformation and damage to waveguides by allowing them to move relative to the frame, maintaining planarity and optical integrity during impact, ensuring device functionality.
Implementation Method 1
The flexures may each have two or more stacked rings. The rings may be coupled together in two or more locations to form multiple springs. The springs may provide cushioning to the waveguide in the event that the head-mounted device is unexpectedly dropped or subject to other forces.
Implementation Method 2
The rings may be coupled together in two or more locations to form multiple springs. The springs may provide cushioning to the waveguide
Implementation Method 3
with an elastomeric stress attenuator to absorb additional forces
Data Source
AI summary
A head-mounted device may have a display system that displays images. The images may be supplied to eye boxes for viewing by a user with waveguides that have output couplers. The waveguides may be supported by a head-mounted support structure. The frame may have eyeglass lens openings that each receive one of the waveguides. The waveguides may be located between outer lens elements and inner lens elements. Flexures may be used to attach the waveguides to the head-mounted support structure. The flexures may include two or more rings that are welded together to form two or more springs. The springs may allow the waveguides to move relative to the head-mounted support structure when a force is applied to the head-mounted structure, thereby pre-venting deformation of the waveguides. An elastomeric stress attenuator may be interposed between the waveguides and the support structure to absorb impacts that would otherwise damage the waveguides.