A process for coating articles is provided. A plurality of electrodes is formed on a surface of the substrate. Also, the wide-angle lens preferably satisfies specified conditions that, together with the use of plastic lenses, joined lens elements, and aspheric surfaces, enables a high performance, compact, wide-angle lens of relatively simple construction to be produced. The apparatus may further include a second signal communication device, which emits or receives a second characteristic signal, wherein the receiver device is designed in such a way that it determines from the signals emitted whether the size part is in a predetermined position with respect to the apparatus. The error signal can be derived from optical signals from an optical pick-up unit. Therefore, even when the thin-film magnetic head tilts so that its electromagnetic transducer side approaches the recording medium when floating up from the recording medium, the amount of thermal expansion caused by the heat from the heat-generating layer is greater in the magnetoresistive device than in the electromagnetic transducer.