We have now seen the many limitations of passive matrix displays and how active matrix displays are able to overcome those problems. However, active matrix displays are extremely expensive to manufacture and yields are commonly very low because the process of creating large sheets of thin-film transistors is far from perfect. Therefore, much research has been done to try to improve the characteristics of the more affordable passive matrix displays. In some very recent cases, the quality of passive matrix displays has gotten very close to that of active matrix displays. Let's now examine a few of the improvements that have been or could be made to passive matrix displays.