Low-Profile Keyset Fabric Cover Layer Design

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Solution Overview

Problem

The challenge in designing low-profile input devices for electronic devices is to maintain an acceptable tactile response and key travel distance while minimizing the stack height, which is constrained by the use of scissor keyset designs and other internal component positioning.

Innovation Solution

The design incorporates a support structure with cavities and flange reliefs, a bezel with openings for key caps, and a fabric cover layer that adheres only to the bezel, allowing key caps to move between positions and provide tactile feedback without increasing the overall device height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a scissor keyset design is used to maintain key stability and tactile response, then the key caps remain horizontal when depressed, but the stack height of the input device increases

Engineering Contradiction:
Improvetactile responseVSAvoidstack height
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent removes the scissor mechanism entirely from the keyset design. Instead of using scissor mechanisms to control key motion, the invention uses a fabric layer that allows key caps to move directly between positions without mechanical intermediaries, thereby eliminating the height constraint while maintaining operational functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a fabric cover layer positioned between the key caps and the support structure. This flexible fabric layer allows key caps to move between first and second positions while maintaining a thin profile, replacing the rigid scissor mechanism with a flexible membrane that provides the necessary motion control without increasing stack height

Inventive Principle:
Principle #30Flexible shells and thin films

2Length of stationary object

If internal components are positioned closer together to reduce device size, then the stack height is reduced, but manufacturing design challenges increase

Engineering Contradiction:
Improvestack heightVSAvoidmanufacturing design
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions into a unified structure. The fabric layer serves multiple purposes: it allows key cap movement, provides structural support, and eliminates the need for separate scissor mechanisms and complex positioning systems. This merging simplifies the manufacturing process while achieving the desired reduced stack height

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fabric cover layer performs multiple functions simultaneously: it acts as a flexible membrane for key motion, provides structural support for the key caps, and serves as a mounting surface for adhesives. This multi-functionality reduces the number of separate components needed, thereby simplifying manufacturing while maintaining the low-profile design

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3729245B1Low-profile keysets and input devices
Publication Date: 2023.06.28 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3729245B1 patent drawingFigure 1
  • EP3729245B1 patent drawingFigure 2
  • EP3729245B1 patent drawingFigure 3A~3B

AI summary

Low-profile keysets and input devices having such low-profile keysets are described. In one example, the input device includes a support structure having a first and second surface; a bezel having a first and second surface, wherein the first surface of the bezel is adjacent to the first surface of the support structure, and the bezel comprises at least one opening; at least one key cap positioned within the at least one opening of the bezel, wherein each key cap is configured to move between a first and second position to trigger a function of the input device; and a fabric cover layer positioned adjacent to the second surface of the bezel, such that the bezel and the at least one key cap are positioned between the fabric cover layer and the support structure, the fabric cover layer is only adhered to the second surface of the bezel.