Hyperextending Eyewear Hinge With FPC Service Loops

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Solution Overview

Problem

Existing eyewear devices, such as smart glasses, face challenges in extending temples to accommodate various head sizes and maintain comfort and stability during use, particularly when incorporating advanced features like cameras and see-through displays.

Innovation Solution

The implementation of a hyperextendable temple hinge with a flexible printed circuit (FPC) and service loops allows for the temple to extend beyond the traditional range, ensuring compatibility with different head sizes while maintaining structural integrity and comfort, and accommodating the necessary electrical connections for cameras and displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the temple is extended to accommodate larger head sizes, then adaptability is improved, but the FPC may become damaged or disconnected due to excessive stretching

Engineering Contradiction:
Improvetemple extension rangeVSAvoidFPC connection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The FPC is designed with dynamic service loops that can expand and contract based on temple extension. The loops transform the linear stretching motion into a rotational motion that the FPC can accommodate without damage, allowing the temple to extend for larger head sizes while maintaining reliable electrical connections.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The service loops change the geometric parameters of the FPC routing by creating additional rotational degrees of freedom. This parameter transformation allows the FPC to accommodate varying temple lengths and extension ranges without compromising connection reliability, enabling adaptability to different head sizes.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the temple is made rigid to maintain structural integrity, then strength is improved, but the temple cannot extend to accommodate various head sizes

Engineering Contradiction:
Improvetemple structural integrityVSAvoidtemple extension capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The temple assembly is segmented into rigid and flexible components. The temple arm itself maintains rigid structural integrity for strength, while the FPC routing incorporates flexible service loops that enable extension. This segmentation allows the temple to be both strong and adaptable to various head sizes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The FPC utilizes flexible thin film structures with service loops that can bend and rotate. These flexible elements are integrated into the rigid temple structure, allowing the temple to extend for different head sizes while the rigid portions maintain structural integrity and strength.

Inventive Principle:
Principle #30Flexible shells and thin films

3Device complexity

If traditional hinge mechanisms are used, then device complexity is minimized, but the temple cannot extend beyond the traditional range

Engineering Contradiction:
Improvehinge mechanism simplicityVSAvoidtemple extension range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The service loops act as an intermediary mechanism between the traditional hinge and the FPC. They mediate the motion transformation, converting simple hinge rotation into expanded movement ranges without requiring complex additional mechanisms. This maintains relative simplicity while achieving extended temple range.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The service loops introduce dynamic motion transformation to the otherwise static hinge mechanism. By converting rotational motion into expanded displacement through the loop geometry, the system achieves extended temple range without adding significant mechanical complexity to the hinge itself.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4107573B1Hyperextending hinge having FPC service loops for eyewear
Publication Date: 2026.03.18 SNAP INC
  • EP4107573B1 patent drawingFigure 1A
  • EP4107573B1 patent drawingFigure 1B
  • EP4107573B1 patent drawingFigure 2A

AI summary

Eyewear having a frame, a hinge, and a hyperextendable temple having a flexible printed circuit (FPC) including service loops. An extender is coupled to the hinge and the temple, and the extender extends with respect to the hinge allowing hyperextension of the temple with respect to the frame. A first service loop allows extension of the FPC when the temple rotates about the hinge, and a second service loop allows the temple to be radially extended away from the hinge.