Flush Touch Actuator with Uniform Force Profile

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Solution Overview

Problem

Conventional touch dimmers have a small operational area and the touch-sensitive area is typically recessed, limiting user interaction to only the center and not allowing actuation across the entire faceplate surface.

Innovation Solution

A load control device with a controllably conductive device and a touch-sensitive actuator that extends through the faceplate opening, providing a larger operational area where the touch-sensitive surface is flush or protrudes above the faceplate, allowing full surface actuation with equal minimum force required across the entire area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the touch-sensitive area is recessed in the faceplate, then the internal structure is protected, but the operational area is limited and user interaction is restricted to only the center

Engineering Contradiction:
Improveoperational areaVSAvoiduser interaction
Core Design Contradiction:
Area of moving objectVSEase of operation

Solution Approach 1:

Instead of recessing the touch-sensitive area into the faceplate, the patent inverts the design by making the touch-sensitive surface extend through and protrude from the faceplate. This allows the entire front surface to be operational, maximizing the active area and enabling users to interact with any point on the faceplate, not just a recessed center region.

Inventive Principle:
Principle #13The other way round (Inversion)

2Area of moving object

If the touch-sensitive area is extended to cover the entire faceplate, then the operational area is maximized, but the actuation force becomes non-uniform across the surface

Engineering Contradiction:
Improveoperational areaVSAvoidactuation force uniformity
Core Design Contradiction:
Area of moving objectVSForce

Solution Approach 1:

The patent applies local quality by varying the structural properties of the faceplate at different locations. The faceplate includes a centrally located first region with a first thickness and a peripherally located second region with a second thickness that is less than the first thickness. This thickness variation compensates for the non-uniform force distribution, ensuring that the actuation force required to activate the touch-sensitive element is substantially uniform across the entire faceplate surface.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the touch-sensitive surface is flush or protruding, then full surface actuation is enabled, but the structural integrity and protection of internal components are reduced

Engineering Contradiction:
Improvefull surface actuationVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The faceplate is designed with non-uniform thickness distribution, where the centrally located first region has a greater thickness to provide structural support and protect internal components, while the peripherally located second region has a reduced thickness to enable full surface actuation. This localized variation in thickness allows the touch-sensitive surface to be substantially flush with or protrude from the front surface of the faceplate while maintaining overall structural integrity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2030485B1Touch sensitive actuator having a uniform actuation force and a maximum active area
Publication Date: 2012.08.15 LUTRON ELECTRONICS CO INC
  • EP2030485B1 patent drawingFigure 1
  • EP2030485B1 patent drawingFigure 2
  • EP2030485B1 patent drawingFigure 3

AI summary

A load control device for controlling the amount of power delivered to an electrical load from an AC power source comprises a touch sensitive device having a touch sensitive front surface responsive to a point actuation. The front surface is adapted to be provided in an opening of a faceplate such that the front surface of the touch sensitive actuator extends through the opening at a distance equal to or greater than the depth of the faceplate. According to the present invention, the operational area of the front surface is maximized to substantially the entire area of the front surface. Further, a minimum magnitude of a force of each of the point actuations is substantially equal at each of the respective positions on the front surface of the touch sensitive actuator, such that the front surface provides a substantially uniform force profile.