Through display ultrasonic touch-screen monitor

A touch-screen monitor, comprising:

• an ultrasonic sensor configured to generate ultrasonic waves and to generate output signals corresponding to detected ultrasonic waves;
• a protective platen comprising a surface receptive to contact by an external object;
• a display TFT pixel array disposed between the protective platen and the ultrasonic sensor;
• and
• a control system configured for communication with the ultrasonic sensor, the control system is further configured to:
• cause the ultrasonic sensor to generate ultrasonic waves that pass through the display TFT pixel array and the protective platen;
• receive output signals from the ultrasonic sensor corresponding to detected ultrasonic waves that are reflected back through the protective platen and the display TFT pixel array;
• and
• determine whether the output signals indicate a presence or an absence of an external object in contact with the surface of the protective platen based, at least in part, on differences between output signals produced at different times.

A system for detecting an object, comprising:

• means for sending ultrasonic waves through a display TFT pixel array and a protective platen, wherein the display TFT pixel array resides between the protective platen and the means for sending ultrasonic waves and wherein the protective platen comprises a surface receptive to contact by an external object;
• means for producing output signals corresponding to detected reflected ultrasonic waves that have passed back through the protective platen and the display TFT pixel array;
• and
• means for determining whether the output signals indicate a presence or an absence of an external object in contact with the surface of the protective platen based, at least in part, on differences between output signals produced at different times.