Example Applications - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 383

Figure 13.54 Cast transponder unit deformed by a pair of tweezers (reproduced by permission
of IWE1, RWTH Aachen, D-52074 Aachen)

External telemetric
components

External coil

Spectacles

Cable to hand-held-unit

Pressure sensor,
internal telemetric components

Eye

Artificial interocular lens

Figure 13.55 An implanted transponder with a pressure sensor, and an antenna coil integrated
into the frame of a pair of glasses make up the system for the continuous measurement of
interocular pressure (reproduced by permission of IWE1, RWTH Aachen, D-52074 Aachen)

and is thus foldable, which makes the implanting of the transponder much easier (see
Figure 13.54). The pressure sensor is micromechanically integrated into he transponder
chip and has a sensitivity of 1.3mbar, which roughly corresponds with the precision
of current tonometer measurements (Ullerich 2001).
So that the transponder can be read continuously, the reader's antenna is integrated
into the frame of a pair of glasses. The control of the coil and the storage of the
measured data takes place with the aid of the reader, which is connected to the glasses
via a cable (Figure 13.55).