Touch panel device and control method and device for eliminating noises in touch panel device

A control device for eliminating noises in a touch panel device including an excitation transducer for exciting a surface acoustic wave upon application of a burst wave and a reception transducer for receiving the surface acoustic wave and converting the same into a reception signal that are arranged at a peripheral portion of a detection area so that a position of an object touching the detection area is detected in accordance with a change in the reception signal, the control device comprising:

• a differential detecting portion for detecting a differential between a reception signal due to a burst wave and another reception signal due to another burst wave;
• a noise detecting portion for detecting a noise when the detected differential exceeds a preset threshold value;
• and
• a control portion for performing a control operation so that the detection of an object based on the reception signal is not performed when a noise is detected.

A touch panel device including an excitation transducer for exciting a surface acoustic wave upon application of a burst wave and a reception transducer for receiving the surface acoustic wave and converting the same into a reception signal that are arranged at a peripheral portion of a detection area, the touch panel device comprising:

• an oscillation portion for producing the burst wave plural times;
• an A/D converter for converting the reception signal into digital reception data;
• an object detecting portion for detecting a position of an object that touches the detection area by comparing the reception data with reference data stored in advance;
• a differential detecting portion for detecting a differential between reception data due to a burst wave and another reception data due to another burst wave;
• a noise detecting portion for detecting a noise when the detected differential exceeds a preset threshold value;
• and
• a control portion for performing a control operation so that the detection of the object based on the reception data is not performed when a noise is detected.