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A Method for Improving Handheld Device Capacitive Button Usability Disclosure Number: IPCOM000021256D
Publication Date: 2004-Jan-08
Document File: 2 page(s) / 33K

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Field of Invention: Handheld devices using capacitive sensors.

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This is the abbreviated version, containing approximately 53% of the total text.

A Method for Improving Handheld Device Capacitive Button Usability

Inventors: Ray Trent

Synaptics Incorporated, San Jose, CA, USA

Field of Invention: Handheld devices using capacitive sensors.

1.    Short Summary

To avoid the potential confusion in this IDF, “button” or “button matrix” will refer to physical switches whereas “keypad” will refer to a capacitive sensor used in lieu of buttons.

The use of a capacitive sensor to replace the buttons of a traditional mobile phone or other similar handheld device presents several usability challenges. Fundamentally, many of these devolve to deciding when the keypad should be active. The invention comprises activating the keypad when a button is pressed, a general-purpose keypad deactivation algorithm, and an indication when the keypad is active.

2.    General Description

The device would have a button, conceptually labeled “Activate Keypad” (or, more likely, it’s iconic equivalent). The keypad would be inactive until the user presses this button, whereupon the keypad would become active until the “current activity” ends, i.e. a “deactivation criterion” is satisfied.

Additionally, the keypad backlight should be turned on when and only when the keypad is active. This provides the user with the information necessary to use their phone, as well as training feedback. A “keypad active” LED or other equally separate but obvious indicator would also be effective.

One usage model of particular importance to mobile phones is when the phone is being used to make a call. The user would press the button to activate the keypad for dialing, and the keypad should be deactivated when the phone attempts to connect the call (typically when the user presses a “send” button). This prevents accidental numbers from being dialed due to the user placing the phone to their ear to listen for the call to be answered.

While a call is in progress, the keypad should only be enabled only while the activation button is depressed. This allows the user to use touch-tone-activated information systems. Use of such systems typically requires frequent switching between listening and using the keypad, which makes a timeout inconvenient. Additionally, there is no general way to know when a touch-tone sequence is “done”. This is why the button needs to be held down in this case… the key-up event is always needed as a deactivation identifier.

Other operating modes will have their own unique needs. For example, MP3 playing mode might need to be interruptible without the user removing the phone from a clip.

A general deactivation algorithm that serves the needs of many of these modes would be to deactivate the keypad after no user activity has been seen for a defined amount of time,...