Capacitive Input Contact Structure for Thin Impact-Prone Devices

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Solution Overview

Problem

Thin user devices face challenges in maintaining electrical contact between input device elements due to impact-related malfunctions, especially in narrow spaces, leading to input malfunctions.

Innovation Solution

An electronic device design featuring a housing with a window, a circuit board, a spacer, and a conductive plate with a flexible contact connected to the circuit board, which forms a capacitance to detect inputs, reducing impact-related malfunctions by maintaining contact even when the window is not electrified.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the user device is made thinner to reduce size, then the device becomes more compact and portable, but there is insufficient space to properly mount input devices and maintain reliable electrical contact

Engineering Contradiction:
Improvedevice thicknessVSAvoidelectrical contact reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs a flexible printed circuit board (FPC) as the substrate for the input device elements. The FPC can be bent and deformed to accommodate impacts and space constraints while maintaining electrical connectivity. This flexible film structure allows the input device to function reliably in thin devices by adapting to dimensional changes without losing electrical contact.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces a spring element that provides elastic force to maintain contact between the movable element and the circuit board. This dynamic mechanism allows the system to adapt to impacts and dimensional changes by using the spring's elastic deformation to preserve reliable electrical contact throughout the range of motion and under impact conditions.

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If the input device elements are positioned closer together to save space, then the device fits in narrower spaces, but impact-related malfunctions become more difficult to prevent

Engineering Contradiction:
Improveinput device mounting spaceVSAvoidimpact resistance
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent positions the movable element and circuit board such that they overlap in the vertical direction, creating a buffer zone before impact can occur. This spatial arrangement provides beforehand cushioning by allowing the spring element to compress and absorb impact energy before critical components are affected, thereby preventing impact-related malfunctions even in compact configurations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The flexible printed circuit board serves as a compliant substrate that can deform under impact forces, absorbing and distributing mechanical stress. This flexibility allows the input device to maintain functionality in narrow spaces while resisting impact-related malfunctions through the FPC's ability to accommodate dimensional changes without fracturing rigid connections.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a rigid structure is used for the input device to maintain stable electrical contact, then contact reliability is improved, but the device cannot accommodate impacts or dimensional changes

Engineering Contradiction:
Improveelectrical contact stabilityVSAvoidimpact accommodation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The flexible printed circuit board replaces rigid circuit board structures with a flexible film substrate. This allows the electrical connections to bend and deform with the input device elements during impacts, maintaining stable electrical contact while accommodating dimensional changes that would be impossible with rigid structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The spring element introduces dynamic elasticity to the electrical contact mechanism. The spring can compress and expand to maintain constant contact force between the movable element and the circuit board, ensuring stable electrical contact while allowing the system to adapt to impacts and dimensional changes that would disrupt rigid connections.

Inventive Principle:
Principle #15Dynamics

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

The design effectively reduces input malfunctions by ensuring consistent electrical contact and improving the reliability of input detection in devices prone to impacts, even when the window is not electrically connected.

Implementation Method 1

a conductive plate 340 with a flexible contact 360-C connected to the circuit board 360, which forms a capacitance to detect inputs

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3329661B1Electronic device including input apparatus
Publication Date: 2021.03.31 SAMSUNG ELECTRONICS CO LTD
  • EP3329661B1 patent drawingFigure 1a
  • EP3329661B1 patent drawingFigure 1b
  • EP3329661B1 patent drawingFigure 2

AI summary

An electronic device is provided. The electronic device includes a housing including a window, configured to a 1st side of the electronic device, and a 2nd side of the electronic device directed in an opposite direction of the 1st side of the electronic device, a circuit board between the 1st side and the 2nd side of the electronic device, and including an input circuit configured to detect an input based on a change in a capacitance, a spacer between the window and the circuit board, and having at least one space formed on one side facing the circuit board, a contact electrically connected to the input circuit by being mounted to one side of the circuit board, and contained in the at least one space, and a conductive plate coupled to the at least one space under the window and separated from the circuit board, and electrically connected to the contact through the at least one space.