[Influence on the physical characteristics of medical color liquid crystal displays with increase in aperture ratio].

We measured the physical characteristics of 2-million(2M)and 3-million(3M)color liquid crystal displays(LCD)whose aperture ratio was increased and compared them with conventional models. The results showed the influence of the increased aperture ratio on the physical characteristics of the LCDs. We evaluated resolution by means of modulation transfer function(MTF)and evaluated granularity by means of noise power spectrum(NPS). Each of the measurements was done with a high-resolution single-lens reflex-type digital camera. A decrease of MTF depending on sub-pixel structures was recognized. A decrease in the cross sub-pixel direction was recognized in the 2M model, and a decrease in the sub-pixel direction was recognized in the 3M model. As for NPS, a reduction was recognized in the sub-pixel and the cross sub-pixel direction in both models. As a result, an improvement in granularity was recognized. The improvement in granularity was large with the color LCDs whose aperture ratio was increased. The increase of an aperture ratio influenced both MTF and NPS, and the results depended on the shape and size of the sub-pixel cells.