KEYPAD APPARATUS HAVING PROXIMITY AND PRESSURE SENSING
Keypad apparatus and methods are described herein. An example keypad includes a dome-switch assembly having a dome aligned relative to a first trace pattern and a second trace pattern of a printed circuit board and a key aligned with the dome. The key is depressible between an initial position, an intermediate position and a depressed position, where the key is to deflect the dome to electrically couple the first and second trace patterns when the key is in the depressed position. A touch sensing film detects a touch on a keycap of the key when the key is in the initial position and a pressure sensing film detects a force on the keycap when the key is in the intermediate position.
1 . A keypad apparatus comprising:
a dome-switch assembly having:
a dome aligned relative to a first trace pattern and a second trace pattern of a printed circuit board;
a key aligned with the dome, the key being depressible between an initial position, an intermediate position and a depressed position, wherein the key is to deflect the dome to electrically couple the first and second trace patterns when the key is in the depressed position;
a touch sensing film to detect a touch on a keycap of the key when the key is in the initial position; and
a pressure sensing film to detect a force on the keycap when the key is in the intermediate position.
2 . The keypad apparatus of claim 1 , wherein the touch sensing film comprises a capacitive sensor having a capacitance sensitive pattern that is associated with the key.
3 . The keypad apparatus of claim 2 , wherein the capacitance sensitive pattern provides a first capacitance output value when an object engages the keycap of the key and a second capacitance output value when the object is away from the keycap of the key, wherein the first capacitance output value is different than the second capacitance output value.
4 . The keypad apparatus of claim 2 , wherein the capacitance sensitive pattern comprises a matrix having a plurality of traces disposed on the touch sensing film.
5 . The keypad apparatus of claim 1 , wherein the touch sensing film comprises an Indium Tin Oxide film.
6 . The keypad apparatus of claim 1 , wherein the pressure sensing film includes a resistance sensitive pattern that is associated with the key.
7 . The keypad apparatus of claim 1 , wherein the pressure sensing film comprises a pressure sensitive ink printed on a dome sheet of the dome-switch assembly.
8 . The keypad apparatus of claim 1 , further comprising a puck disposed between the pressure sensing film and the dome, the puck comprising a material substantially similar to the material of the pressure sensing film.
9 . The keypad apparatus of claim 1 , wherein the touch sensing film and the pressure sensing film are disposed between an actuator associated with the keycap and the dome.
10 . The keypad apparatus of claim 9 , wherein the actuator is to directly contact the touch sensing film.
11 . The keypad apparatus of claim 8 , wherein the actuator deflects the touch sensing film and the pressure sensing film toward the dome when a keycap associated with the dome is in the depressed position.
12 . The keypad apparatus of claim 1 , further comprising an insulating material disposed between a first surface of the touch sensing film and the dome.
13 . A keypad assembly comprising:
a dome-switch;
a pressure sensor disposed between a dome of the dome-switch and a keycap of the keypad assembly; and
a touch sensor disposed between the keycap and a printed circuit board.
14 . The keypad assembly of claim 13 , wherein a key associated with the dome-switch is movable between an initial position, an intermediate position and a depressible position.
15 . The keypad assembly of claim 14 , wherein the touch sensor is to detect a touch when the key is in the initial position and the dome-switch is not activated.
16 . The keypad assembly of claim 14 , wherein the pressure sensor is to detect a force when the key is in the intermediate position and the dome-switch is not activated.
17 . The keypad assembly of claim 13 , wherein the touch sensor is directly coupled to the pressure sensor.
18 . The keypad assembly of claim 13 , further comprising an insulating material disposed between the touch sensor and the pressure sensor.
19 . A keypad comprising:
a dome sheet having a plurality of domes disposed over a printed circuit board;
a pressure sensing ink printed on the dome sheet; and
a proximity sensing film disposed adjacent the pressure sensing ink between a keycap of the keypad and the printed circuit board.
20 . The keypad of claim 19 , further comprising an insulating material disposed between the pressure sensing ink and the proximity sensing film.