A system and method for mild cognitive impairment class discovery using gene expression data are provided. A select device selects the analog waveform driving signal as a driving signal for a touch panel in an analog waveform mode, and selects the digital waveform driving signal as a driving signal for the touch panel in a digital waveform mode. Thus a liquid such as muddy water which has entered from the recoil cover can be removed simply by pulling out the drain cap. This compensation not only makes the apodization over the pupil become more symmetric but also makes the intensity variation smaller overall.