In a recording medium reproducing apparatus that can reproduce a recording medium such as a CD-R or CD-RW recording therein compressed audio data, a track number of three or more digits can be indicated using an existing display portion that is designed to indicate a track number in two digits. The expandable bookcase is attachable to any number or combination of bookcase extension sections and corner sections. The first circuit can have a high-voltage power supply unit which charges a high-voltage capacitor which can be applied to the anode via a high-voltage switch. This lens is used for corrective presbyopia vision, specially corrective for mediate and near distance presbyopia vision. An electrical connector, such as an electrical snap connector, is also provided herein, which is suitable for electrically coupling two or more microcomponents. Further boron ions are implanted near the center of the field oxide film in the thickness direction, and a second high energy boron implantation P layer is formed.