An optical pickup including a stem; a substrate mounted on the stem; a laser diode mounted on, and electrically insulated from, the substrate; and a photodetector provided on the substrate for detecting return light from an object to be irradiated. As a result, the mixture in the recess is kept at a favorable airfuel ratio and the engine is enabled to operate in a stratified charge lean burn mode over a wide operating range. The data records may contain the identity of the dispenser, tag and any attribute of a received signal, such as frequency band or signal strength, or other attribute indicative of proximity. The cleaning substrate provides a controlled release of the chemical actives on the surface to be cleaned. The shutter mechanism is away from the terminal module and includes a mounting member assembled to the ejector and the shell and a door member.