A solid state lasing structure comprising a field effect transistor in which source and drain electrodes are disposed on a semiconducting light emitting organic polymer forming an active layer on a gate whereby current between the source and drain electrodes defines and flows along a channel in the active layer to define a recombination and emission zone. The drug delivery device is a drug delivery system adapted for whole implantation in a subject and to provide pain relief by delivery of fentanyl or a fentanyl congener over a protracted period of time. A processing section of a control device is constituted with microcomputers of an indoor and outdoor control sections, while a detecting section of the control device includes temperature sensor, detection means for detecting pressure, detection means for detecting flow rate, detection means for detecting voltagecurrent, and detection means for detecting frequency. A display section highlights the tracking object character string when the tracking object character string extends beyond the photographable area of the image pickup device and displays an arrow showing the relative direction.