An optical interference display unit with a first electrode, a second electrode and support structures located between the two electrodes is provided. The distortion removal system uses the signal previously quantized with the sample-by-sample quantization techniques to determine an expected quantization distortion. An exemplary path loss-related characteristic is path loss as determined by measuring received signal strength at wireless terminals based on signals transmitted at known powers by a plurality of the system’s base stations. At an instant when the development of the resist film is finished, a second developing solution lower in concentration than the developing solution is supplied to the substrate.