Bistable Eyewear Hinges for One-Handed Secure Fitting

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Solution Overview

Problem

Existing eyewear devices, such as smart glasses, require two-handed operation for handling, which can be cumbersome and inefficient, especially during frequent use.

Innovation Solution

The eyewear device incorporates bistable hinges with magnetic locking features and elastic springs that allow single-handed operation, enabling the device to transition between closed, partially open, and fully open configurations for easy placement and removal, using a single hand.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional eyewear devices use simple hinges without locking mechanisms, then the device structure is simple, but the device cannot be securely fitted on the user's head during physical activities

Engineering Contradiction:
Improvesecure fittingVSAvoidhinge structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hinge system transitions from a static simple hinge to a dynamic bistable mechanism that can switch between open and closed configurations. The bistable hinge uses spring elements and magnetic locks to provide two stable states: open for easy placement and closed for secure fitting during activities, resolving the contradiction between simplicity and security.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The magnetic locking mechanism automatically engages when the arms are folded behind the head, providing self-service security without requiring user intervention. The spring-loaded bistable hinge automatically transitions between states, eliminating the need for complex manual locking operations while ensuring reliable secure fitting.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If eyewear devices require two-handed operation for opening and closing, then the device can be handled securely, but the operation becomes cumbersome and inefficient during frequent use

Engineering Contradiction:
Improvesingle-handed operationVSAvoidhandling stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bistable hinge mechanism with spring elements and magnetic locks provides self-service functionality that enables single-handed operation. The automatic transition between open and closed configurations eliminates the need for two-handed manipulation, allowing users to quickly put on and remove the device with one hand while maintaining secure handling through the stable mechanical states.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the arms are always kept open for easy access, then the device is easily removable, but the device occupies more space and may interfere with the user's vision or comfort

Engineering Contradiction:
Improveeasy removalVSAvoiddevice configuration
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The device dynamically changes its configuration between open and closed states based on usage conditions. The bistable hinge allows the arms to automatically fold behind the head during physical activities, transitioning from an extended vision-obstructing position to a compact behind-head position, thus resolving the contradiction between easy access and comfortable wear.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the device automatically transitions between configurations, then the operation is simplified, but the mechanism becomes more complex requiring additional components

Engineering Contradiction:
Improveautomatic transitionVSAvoidhinge mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The automatic transition is achieved through self-service mechanical elements: spring-loaded bistable hinges and magnetic locks that automatically engage and disengage based on the device's state. These passive mechanical systems require no external power or complex control mechanisms, enabling automatic configuration changes while keeping the overall device complexity manageable through elegant use of fundamental mechanical principles.

Inventive Principle:
Principle #25Self-service

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

Enables single-handed operation and secure fitting of the eyewear device on the user's head, facilitating easy handling and reducing the effort required for frequent use, particularly during physical activities.

Implementation Method 1

Each of said first hinges may comprise a spring (or some other resilient means) to move the respective arm to said partially open configuration

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The locking feature of the frame may be a magnetic locking feature. Furthermore, the second hinges of said first and second arms may be magnetically locked to said locking feature in the closed configuration

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP4343413B1Eyewear device
Publication Date: 2026.03.04 NOKIA TECHNOLOGIES OY
  • EP4343413B1 patent drawingFigure 1~2
  • EP4343413B1 patent drawingFigure 3~4
  • EP4343413B1 patent drawingFigure 5~6

AI summary

An eyewear device is described comprising: a frame having a locking feature; a first arm having a frame end and a distal end; and a second arm having a frame end and a distal end. The first arm has a first hinge at the frame end attaching the first arm to the frame and a second hinge between the frame end and the distal end. The second arm has a first hinge at the frame end attaching the second arm to the frame and a second hinge between the frame end and the distal end. In a closed configuration of the eyewear device, the second hinges of the first and second arms are releasably locked to the locking feature of the frame. The first hinges of the first and second arms are elastic in order to move the respective first and second arms from the closed configuration to a partially open configuration on release of the releasable locking of the respective arm to the locking feature of the frame.