Tactile Feedback Mechanisms for Smooth Touch Surface Keyboards
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Solution Overview
Problem
Touch surface keyboards face challenges in providing tactile feedback for key positions away from the home row without disrupting pointing and gesturing motions, and existing solutions either complicate the design with individual actuators or create an uncomfortable surface with raised ridges.
Innovation Solution
The implementation of tactile feedback mechanisms such as Braille-like dots, bars, or an articulating frame that extends during typing and retracts during pointing, along with a rigid frame beneath the surface with compressible key centers, allows for distinct tactile feedback without impeding motion, and can be configured to simulate concave key cap depressions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If raised ridges are used to indicate key edges, then tactile feedback for key positions is improved, but the surface becomes rough and impedes pointing motions
Solution Approach 1:
The tactile feedback mechanism is segmented into discrete domes positioned at specific key locations rather than continuous raised ridges. This segmentation provides localized tactile cues for key positions while leaving the spaces between keys smooth for pointing motions.
Solution Approach 2:
The surface has different local qualities: raised domes at key positions provide tactile feedback, while the areas between keys remain smooth and flat for comfortable pointing and gesturing motions.
2Loss of information
If individual actuators are used under each key to provide dynamic tactility, then tactile feedback precision is improved, but mechanical complexity and cost increase
Solution Approach 1:
The domes are formed directly in the touch-sensitive surface material itself, making the surface self-structuring rather than requiring external actuators. The material inherently provides the tactile feedback geometry without additional mechanical components.
Solution Approach 2:
The mechanical actuator system is replaced with a static geometric structure formed in the surface material. The tactile feedback is provided by the physical geometry of domes rather than by active mechanical movement, eliminating the need for individual actuators under each key.
3Measurement precision
If a single raised dot is placed on home row keys, then hand alignment is improved, but feedback for peripheral key positions is lost
Solution Approach 1:
Instead of a single alignment dot, multiple discrete domes are placed at different key positions including home row and peripheral keys. This segmentation provides distributed tactile feedback across the entire keyboard surface.
Solution Approach 2:
The dome structure serves multiple functions: it provides hand alignment feedback for home row keys and simultaneously provides position feedback for peripheral keys, eliminating the need for separate alignment and position indication systems.
Data Source
AI summary
Disclosed are four arrangements for providing tactility on a touch surface keyboard. One approach is to provide tactile feedback mechanisms, such as dots, bars, or other shapes on all or many keys. In another embodiment, an articulating frame may be provided that extends when the surface is being used in a typing mode and retracts when the surface is used in some other mode, e.g., a pointing mode. The articulating frame may provide key edge ridges that define the boundaries of the key regions or may provide tactile feedback mechanisms within the key regions. The articulating frame may also be configured to cause concave depressions similar to mechanical key caps in the surface. In another embodiment, a rigid, non-articulating frame may be provided beneath the surface. A user will then feel higher resistance when pressing away from the key centers, but will feel a softer resistance at the key center.