If 1920x1200 screens were put on 17.1" laptops; why are 1920x1080 laptops 17.3" or 18.4?????

Should the current lower res 1920x1080 laptops be smaller than 17.1?????

 

Resolution has almost nothing to do with physical size; note that you can put a 1920x1080 screen in the 13.3" Sony Vaio Z. However, for a given approximate size, thanks to geometry, a 16:9 ratio screen will have a longer diagonal than a 16:10 screen, because it's more rectangular. Basically, given the same area, the farther away from a square shape you get, the longer the diagonal becomes. As a 16:9 screen is narrower and farther away from a square than a 16:10 screen, its diagonal increases in length.

 

So the area of the 16:9 and 16:10 screens are the same (for ~17 inch laptops say)?
I thought they just chopped off a slice lengthwise from 1920x1200 screens.

 

16:9 screens are physically wider but shorter than 16:10 screens. And 16:10 screens have more area than 16:9 screens of similar sizes.

 

You're comparing two very different things. Physical screen size and resolution are not related, so just because you have a smaller physical screen size, doesn't mean the resolution will be proportional to it.

 

Yeah sony have always put almost absurd resolutions on some small devices.

 

Well, let's do a little quick math, shall we?

Starting with the 16:9 screen.

The dimensions of a 16:9 screen will be 16x by 9x, with a diagonal of 17.3". So we have (16x)² + (9x)² = (17.3)², which comes out to 256x² + 81x² = 299.29, so 337x² = 299.29, x² = 0.8881, x = 0.9424, and the dimensions will be 15.08" by 8.48", with an area of 127.88 in².

The dimensions of a 16:10 screen will be 16x by 10x, with a diagonal of 17.1".
So, (16x)² + (10x)² = (17.1)², which comes out to 256x² + 100x² = 292.41, 356x² = 292.41, x² = 0.8214, x = 0.9063, and the dimensions would be 14.5" by 9.06", with an area of 131.37 in².

I think a lot of 17" screens weren't 17.1", though, but 17". My NX860XL is listed as having screen dimensions of 14.4" and 9", which would fit a diagonal of 17", and with an area of 129.6 in².

You'll note that the small increase in diagonal size here has actually resulted in the loss of total surface area, irregardless of actual resolution, due to the aspect change.

 

Simple answer - 1920x1080 is FullHD standard.
If you watch FullHD movies on 16:9 screen you will watch them in native res, pixel-perfect.

With 16:10 screen it's the same, only with black letterboxing on top and bottom.

 

Good theory, but more than half of all the movies that are relesed are presented in their original theatric aspect ratio 1.85:1 or 2.35:1. And these equate closer to 17:9 and 21:9 so you still end up with black bars at the top and bottom even on a 16:9 display. So manufactures can pry my 120 pixels from my cold dead hand. ;-)

 

It does not matter what aspect ratios movies use.
FullHD is standard for digital TV and content (bluRay, DVD, etc, etc), it was heavily pushed by LCD panel manufacturers for TVs.

I am just explaining why such choice of resolutions for panels.

Personally I can't stomach 16:9 screens. They maybe good for watching movies, but not for anything else - and who buys laptop primarily to watch movies?

 

Interesting approach. And here I was using trigonometry to get the answer.

(Diagonal)²*(sin(2arctan(Ratio)))/2=Area
(17.3)²*(sin(2arctan(16/9)))/2=127.887
(17.1)²*(sin(2arctan(16/10)))/2=131.42

 

Well, I stuck with the pythagorean theroem because most people are familiar with it, and thus it's easier to follow. People tend not to remember their trigonometry nearly as well.

 

I like your method Judicator, very nice

 

Well...actually, in this case they are. But that's because of industry standards, not physical requirements. However, they are not necessarily directly proportional.

Indeed. However, in this non perfect world, we introduce the 16:9 standard--which is the closet "compromise" to all the various ratios. Otherwise, you'd really have a mess of screens ratios flooding the market.

 

Well there has been a shortage of high res LED backlit displays, especially that are affordable. You can get them on ebay now for a reasonable price. However this does not mean they are available in the quantities that Acer would need.