The specifications of TFT modules look very similar. However, especially in terms of optics, a data sheet can only imperfectly reflect the characteristics of a display. But what do terms like response time and viewing angle actually mean, how are contrast and luminance determined? The specification of a TFT display contains a lot of information. This includes mechanical, electrical and optical properties. Although uniform terminology and measurement methods have become established, it is still worthwhile to check the specified values in detail, such as viewing angle (applies at what contrast?) or backlight life (applies at what temperature?). With the knowledge of the terms and their definition, the comparison and selection of a suitable display is not difficult.