How do they decide the length and width of screens and monitors?

Question

I measured a few of mine expecting them to have a pattern, and maybe that widescreens were by the golden ratio. However, my full screens are 1.32 (16x12.5) and 1.185 (16/13.5). My laptop is 1.529 (13/8.5). A previous question here on yahoo told me a widescreen was 16x9, or 1.78.

Where is the pattern, or what is the factor? My next guess is that it would have something to do with the angle of the diagonal, but that would be entirely dependent on the ratio of the lengths.

How do they decide the distributions?

Answer 1

Widescreen for televisions is 16:9. For PC's it is usually 16:10, and in some cases 16:9. "Regular" screens have a ratio of 4:3.

Part of it may have to do with how they measure. On a CRT monitor I don't know if they measure the glass with or without the curve. On flat panels I would expect it to simply be corner to corner but who knows how accurate that is. It would not surprise me if some companies claim  their screens to be bigger than they really are.

As for the laptop it may have a non-standard screen size. Some laptops are inbetween standard and widescreen to account for their portable form factor.

16x12.5 is pretty close (16x12 would be 4x3, the expected ratio) 16x13.5 seems a little weird. That may be a non-standard monitor, or the company might just have very very poor measuring skills.

In any case, standard ratios are 4:3 and 16:9 for TV's + 4:3 and 16:10 for LCD PC monitors.