A photoresist is provided with an opening as a dummy pattern in a space area, i. The device, an optical mark reader has an array of photo sensors with light-emitting diodes, which are driven by digital-to-analog converters, which are in turn controlled by a microcontroller. The SIMD floating-point unit also includes means for generating a first slice and a second slice. A calibration member is adjacent the clutch assembly for engagement with the second protuberance.