Knob-on-Display Assembly With Fixed Electrodes and Tactile Push
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Solution Overview
Problem
Existing knob on display (KoD) devices face challenges with mechanical complexity, large Z push travel distance, and issues with electrode pads moving towards the touch screen, leading to reliability and adhesion problems.
Innovation Solution
The design incorporates a tactile dome switch with a push electrode pad and a rotation electrode pad that remain in constant engagement proximity to the touch sensor, using a flexible printed circuit or printed circuit board to connect these pads to the touch surface, providing a stable and reduced Z height, and utilizing a base assembly for enhanced adhesion and protection from foreign elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrode pads are allowed to move towards the touch screen during operation, then the KoD can provide tactile feedback and mechanical interaction, but adhesion problems and reliability issues occur
Solution Approach 1:
The KoD device is divided into separate functional components: a fixed base assembly that maintains constant engagement with the touch sensor, and a separate actuator mechanism that provides tactile feedback without compromising the electrode connection. This segmentation allows the electrode pads to remain stationary while the actuator moves independently to provide mechanical interaction.
Solution Approach 2:
The patent introduces a Z-height dimension solution by using a thin-film or flexible circuit board that maintains constant electrical engagement while allowing the actuator to move in a different spatial plane. This dimensional separation allows tactile feedback mechanisms to operate without affecting the electrode-pad-to-touchscreen engagement distance.
2Reliability
If mechanical components are reduced in the KoD design, then reliability and adhesion are improved, but tactile feedback capability may be compromised
Solution Approach 1:
The patent replaces traditional mechanical switch mechanisms with a capacitive touch sensor-based system. The tactile feedback is achieved through capacitive coupling between the KoD actuator and the touch sensor, eliminating the need for mechanical contacts or moving electrode pads. This substitution maintains reliability while preserving tactile interaction capability.
Solution Approach 2:
A flexible circuit board or thin-film intermediary is introduced between the electrode pads and the touch screen. This intermediary maintains constant electrical engagement while allowing the actuator to move independently, providing tactile feedback without requiring mechanical components to move towards the touch screen.
3Length of moving object
If the Z push travel distance is reduced, then the KoD profile is lowered and integration is improved, but mechanical actuation becomes more difficult
Solution Approach 1:
The patent employs a spring-loaded or elastomeric actuator mechanism that uses elastic deformation to provide push travel. This allows the KoD to maintain a low Z-profile while still providing adequate actuation distance through the elastic recovery of the spring or elastomer material, enabling mechanical actuation without increasing overall device height.
Solution Approach 2:
The patent changes the material parameters of the actuator mechanism, using materials with appropriate elastic modulus and damping characteristics. This allows the actuator to provide sufficient mechanical feedback within a reduced Z-height envelope by optimizing the balance between material stiffness and travel distance.
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
This configuration reduces mechanical components, enhances reliability, provides tactile feedback, and improves adhesion, ensuring a stable and reliable electrical connection while preventing foreign elements from entering the electrode area, thus enhancing the overall performance and durability of the KoD device.
Implementation Method 1
a tactile dome switch with a push electrode pad
Data Source
AI summary
One or more examples relate to a knob-on-display. An apparatus of such a knob-on-display includes a touch surface, a dome switch pad, a dome switch, a rotation electrode pad, and an electrically conductive structure. The touch surface may include an electrically conductive material, the touch surface movable to a released position and to a depressed position. The dome switch may include an electrically conductive material. The dome switch may be physically mounted to and electrically connected to the dome switch pad. The rotation electrode pad may be in engagement proximity to a touch sensor of a touch screen device in both the released position and the depressed position. The electrically conductive structure may be physically and electrically connected to the dome switch pad and the rotation electrode pad, the electrically conductive structure defining a continuous electrically conductive path from the rotation electrode pad, through the dome switch, to the electrically conductive material of the touch surface in both the released position and the depressed position.