Environmentally isolated keypad assembly with tactile feedback

An optical keypad assembly comprising:

• a window having a first surface exposed to an exterior of the enclosure and a second surface exposed to the interior of the enclosure;
• a plurality of electrical components housed within the interior of an enclosure, the plurality of electrical components comprising:
• a printed circuit board, and
• at least one array mounted on the printed circuit board, the at least one array including a plurality of optical-sensing elements;
• a keypad membrane positioned on the window and overlying an entirety of the plurality of optical-sensing elements, thereby shielding at least the plurality of optical-sensing elements from ambient lighting, the keypad membrane comprising:
• a top surface and a bottom surface extending generally parallel to each other,
• a plurality of cutouts extending from the bottom surface with each having a respective target surface, the plurality of optical-sensing elements configured to monitor a predetermined characteristic of the respective target surface, and
• at least one key, each having visible indicia disposed on the top surface and arranged in a pattern corresponding to the target surface or the respective location of the respective plurality of optical-sensing elements.

An optical keypad assembly comprising:

• a window having a first surface exposed to an exterior of the enclosure and a second surface exposed to the interior of the enclosure, the window being secured to the enclosure and having a seal to prevent ingress of contaminants into the interior of the enclosure;
• a plurality of electrical components housed within the interior of an enclosure, the plurality of electrical components comprising:
• a printed circuit board, and
• at least one array mounted on the printed circuit board, the at least one array including a plurality of optical-sensing elements;
• a keypad membrane comprising:
• a top surface and a bottom surface extending generally parallel to each other,
• a plurality of cutouts extending from the bottom surface with each having a respective target surface, the plurality of optical-sensing elements configured to monitor a predetermined characteristic of the respective target surface, and
• at least one key, each having visible indicia disposed on the top surface and arranged in a pattern corresponding to the target surface or the respective location of the respective plurality of optical-sensing elements.

A method of interacting with an enclosure installed in a hazardous environment using a human machine interface (HMI), the method comprising:

• providing an optical keypad assembly comprising:
• a window having a first surface exposed to an exterior of the enclosure and a second surface exposed to an interior of the enclosure;
• a printed circuit board,
• at least one array mounted on the printed circuit board, the at least one array including a plurality of optical-sensing elements, and
• a keypad membrane comprising:
• a top surface and a bottom surface extending generally parallel to each other,
• a plurality of cutouts extending from the bottom surface with each having a respective target surface, and
• at least one key, each having visible indicia disposed on the top surface;
• providing an input comprising a press force applied to the at least one key for a duration, thereby causing a displacement of at least the target surface;
• detecting, via the plurality of optical-sensing elements, the displacement of at least the target surface;
• providing a tactile feedback from the keypad membrane in response to the input, the tactile feedback comprising a localized deformation of at least the respective target surface that received the press force;
• and
• detecting a liftoff from the at least one key, thereby causing another displacement of at least the target surface of the keypad membrane.