Position detecting device including antenna function and display device

A position detecting device including an antenna function, the position detecting device comprising:

• a plurality of electrodes including a plurality of shared electrodes separated by spaces;
• a position detection circuit configured to detect a position by energizing the plurality of electrodes and using electric fields generated between the plurality of electrodes;
• an antenna circuit configured to perform wireless communication by energizing the plurality of shared electrodes and using magnetic fields generated in the spaces;
• at least one switch connected to the plurality of shared electrodes among the plurality of electrodes, the position detection circuit, and the antenna circuit, the at least one switch being configured to selectively connect either the position detection circuit or the antenna circuit to the plurality of shared electrodes, wherein:
• the at least one switch is arranged to be selectively connected to the plurality of shared electrodes among the plurality of electrodes,
• the antenna circuit includes:
• a plurality of short-circuit wiring lines,
• a short-circuit changeover switch individually connected to all of the plurality of electrodes and connected to some of the plurality of short-circuit wiring lines, the short-circuit changeover switch being configured to switch conduction/non-conduction between the plurality of electrodes and the plurality of short-circuit wiring lines,
• a plurality of second switch connection portions connected to a plurality of short-circuit changeover switches including the short-circuit changeover switch,
• an external connection wiring line configured to connect two shared electrodes included in the plurality of shared electrodes and separated by the spaces to an external antenna drive unit,
• a short-circuit wiring line from the plurality of short-circuit wiring lines configured to short-circuit the two shared electrodes, and
• a plurality of switch connection portions connected to a plurality of switches individually connected to the plurality of electrodes;
• a first substrate provided with at least the plurality of switches;
• a second substrate provided with at least one of the external connection wiring line, the short-circuit wiring line, and the plurality of switch connection portions, the second substrate being mounted to the first substrate, wherein the external connection wiring line and the short-circuit wiring line are selectively connected to the plurality of switch connection portions;
• and
• a third substrate provided with the plurality of short-circuit wiring lines and not provided with the external connection wiring line, the third substrate being mounted to the first substrate on a side opposite to the second substrate, wherein:
• when the number of the plurality of shared electrodes is 2n,
• two external connection wiring lines and (n−1) short-circuit wiring lines are provided on the second substrate,
• n short-circuit wiring lines and the plurality of second switch connection portions are provided on the third substrate,
• the plurality of short-circuit wiring lines are selectively connected to the plurality of second switch connection portions, and
• n is a natural number.