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A Touch-Typing Touch Screen Keyboard with Tactile Feedback Disclosure Number: IPCOM000010977D
Original Publication Date: 2003-Feb-05
Included in the Prior Art Database: 2003-Feb-05
Document File: 3 page(s) / 47K

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This invention disclosure publication describes a method to mimic the tactile feedback of a mechanical key in order to improve human performance and preference when using non-mechanical, capacitive sensing surfaces.

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A Touch-Typing Touch Screen Keyboard with Tactile Feedback

The current invention describes a method of providing tactile feedback to mimic the feedback a mechanical button provides for computer touchscreen devices using non-mechanical, capacitive sensing surfaces. Touchscreens can be used to create input devices that are more configurable, for example, non-mechanical "soft" keypads provided with touchscreen devices. The liquid crystal display (LCD) and sensing areas can be remapped and configured easily through software to produce a keyboard that can "morph" into many forms to accommodate different languages, different preferred layouts, and alternate input formats. Despite the advantages of touchscreens, studies indicate that users prefer, and are more accurate with, mechanical buttons. This invention creates the sensation of tactile feedback by using the area of the finger contact as an analog of force, and outfitting the sensing to create point source or directional vibrations as sensational indicators in the same patterns as the force curve of a mechanical key mechanism. Thus, the tactile feedback-learning cycle that underlies some of the human performance advantages of a mechanical key mechanism can be realized by non-mechanical designs.

It is well established that user controls (computer keyboard, push buttons, etc.) require tactile user feedback to maximize human performance and minimize error. The mechanical principles of such user controls are well understood and studied, and are embodied in international standards such as ISO 9241-7. This standard outlines, among other things, the required force curve characteristics of a computer keyboard. Specifically, ISO 9241-7 describes the key parameters of keyboard design including: preload, peak force, travel, drop force, mechanical and electrical activation points , and overtravel. Three of these parameters are most important: Preload is physical resistance so that the user can rest his or her fingers on the keys without activating a key, avoiding the fatigue of "hovering". Drop Force is the tactile cue that key activation is occurring, so the user can "start stopping" their finger movement. Overtravel provides the "soft landing" at the end of key travel to avoid the discomfort of constant "hitting bottom".

The current invention describes a way to mimic the user feedback mechanisms that make mechanical keys comfortable to use while working with a touchscreen. Such an invention would provide users a way of sensing when a key stroke has registered, through tiny vibrations in addition to any auditory and visual feedback. A soft keyboard with tactile feedback achieves an advantage over current touch screen keyboards by simulating the preload force, the tactile feedback of the drop force, and the soft landing of overtravel.

Controls should have a preload force that is the initial force required to make the control move. This is generally calculated to be the resting force, or weight...