Dual Stiffness Suspension for Haptic Touch Screen Feedback
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Solution Overview
Problem
Existing haptic touch screens face challenges in providing effective haptic feedback while maintaining a rigid feel to the user, as conventional suspension systems either limit the mass of the system or compromise on stability when allowing movement for haptic effects.
Innovation Solution
A dual stiffness suspension system is introduced, comprising a first element with higher stiffness and a second element with lower stiffness, allowing movement in one direction while restricting it in the opposing direction, thereby enabling haptic feedback while maintaining a rigid feel during user interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a compliant suspension system is used to allow screen movement for haptic feedback, then haptic effects can be provided to the user, but the screen feels less rigid to the user
Solution Approach 1:
The suspension system is segmented into multiple independent elements (first suspension elements and second suspension elements) with different stiffness characteristics. This segmentation allows each element to handle specific directional forces independently, enabling the screen to feel rigid in the vertical direction while allowing controlled movement in the horizontal direction for haptic feedback.
Solution Approach 2:
Different suspension elements are assigned different local qualities (stiffness characteristics). The first suspension elements have higher stiffness to maintain vertical rigidity, while the second suspension elements have lower stiffness to allow horizontal movement. This local differentiation of properties resolves the contradiction between overall rigidity and localized compliance for haptic effects.
2Stability of the object's composition
If a rigid mounting system is used for the touch screen, then the screen feels stable to the user, but haptic feedback cannot be effectively provided
Solution Approach 1:
The suspension system transitions from a static rigid mounting to a dynamic system that adapts its compliance based on the direction and type of force applied. The system dynamically allows movement when haptic forces are applied horizontally while maintaining rigidity when vertical forces are applied during normal touch interaction, effectively providing both stability and haptic capability.
Solution Approach 2:
The mounting system incorporates local quality variations through different suspension elements with differentiated stiffness properties. This allows specific regions of the screen mounting to be compliant for haptic actuation while other regions remain rigid for structural stability, resolving the contradiction between overall stability and localized adaptability.
3Adaptability or versatility
If the suspension system allows movement in all directions, then haptic feedback is effective, but the screen becomes unstable during user interaction
Solution Approach 1:
The suspension system is divided into directionally specialized elements: first suspension elements constrain movement in the vertical direction to maintain stability during user interaction, while second suspension elements allow controlled movement in the horizontal direction to enable effective haptic feedback. This directional segmentation resolves the contradiction between movement freedom and interaction stability.
Solution Approach 2:
The suspension system employs asymmetric stiffness characteristics in different spatial directions. The vertical direction features high stiffness for stability during touch interaction, while the horizontal direction features low stiffness for haptic movement. This asymmetric design allows the system to provide both stability and haptic effectiveness simultaneously.
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 dual stiffness suspension system effectively allows for haptic feedback by permitting movement along desired axes while restricting movement in other directions, enhancing user experience by providing intuitive and natural interaction with haptic devices.
Implementation Method 1
The at least one dual stiffness suspension system has a first element of a first stiffness and a second element of a second stiffness, the first stiffness being stiffer than the second stiffness
Implementation Method 2
The at least one dual stiffness suspension system has a first element of a first stiffness and a second element of a second stiffness, the first stiffness being stiffer than the second stiffness
Data Source
AI summary
Devices disclosed herein include a housing component, a touch screen, a haptic actuator for moving the touch screen relative to the housing component, and at least one dual stiffness suspension system that couples the touch screen and housing component together such that the touch screen is movable relative to the housing component. The dual stiffness suspension system has a first element of a first stiffness and a second element of a second stiffness which is stiffer than the first stiffness. The dual stiffness suspension system is configured to limit movement between the touch screen and the housing component in a first direction due to the first element of the dual stiffness suspension system while also being configured to allow movement of the touch screen relative to the housing component in a second opposing direction due to the second element of the dual stiffness suspension system.