Tv screens: why are measured diagonally?

Recently, the development of technologies has gone hand in hand with the evolution of main user interface: the screens.

TV coming into homes

Thanks to the diffusion of the television this technology entered into the lives of ordinary people. The first TVs were so different from nowadays televisions: with black and white screens, less defined images and much more bulky dimensions. This is because the cathode ray tube needed a certain distance between the back and the front screen to work.

 

Size does matters: from diameter to diagonal

Initially, the cathode ray tube had a round shape. Its diameter was therefore used to define the size of a television. Subsequently, with the introduction of rectangular tubes, the diagonal was the largest dimension to be measured. Since then, it has continued to be used for all types of screens.

Potentially this measurement mode could be problematic since it does not allow to accurately and immediately identify the size of a screen. Apparently, however, the advantages of this method of measurement have always been sufficiently superior to the disadvantages and have meant that it has never been really put into question.

Expressing the size of the TV in inches is a standard method used all over the world. This has obvious advantages from the point of view of production – it is not necessary to produce devices of different sizes for different markets – and marketing – it is possible to “speak the same language”. Furthermore, it made it possible for consumers to always manage to reduce a certain inches to a size.