15" screen = 13" picture?

It may be too simple but I am confused:

In the computer shop, what 15" screen means:
   the dialog length of the picture ?
   the dialog length of the front face of the tube ?
   the dialog length of the front face of the whole box ?
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RoadWarriorConnect With a Mentor Commented:
The size quoted is the diagonal maximum dimension of the CRT (the tube) of which probably 1/2 an inch is hidden under the plastic all round, and another 1/2 inch all round may be unusable due to edge curvature, scan limits etc.

Picture size can't be quoted effectively for a sold alone CRT monitor, since it can vary with the video card and scan rates used.

Picture size can be quoted for a LCD monitor, because at the monitors maximum resolution all pixels are used. Pixels are fixed on a LCD monitor, they end up where the graphics card and analogue video circuitry puts them on a CRT.

It varies greatly with manufacturer, I had a nice "14 inch" monitor, which gave picture area equivalent to many 15 inch models. (It was an Amstrad SVGA model by the way, don't know if Amstrad made it or just branded it)

Where the box is not much bigger than the tube it may seem like this dimension is quoted, since tube sizes over the integer inch figure by a fraction are "upgraded" by the sales people to the next integer inch figure, i.e. a 13.2 inch tube would be called a 14 inch tube.

Televisons (and usually composite video monitors) usually have their size quoted as the diagonal of the viewable area, which is what sticks out of the case, it may or may not actually get a picture on it.


Road Warrior

victorlongAuthor Commented:
Adjusted points from 35 to 40

Monitor sizes have traditionally been specified in terms of the size of the glass of the CRT used in the manufacture. Actual image sizes on CRT monitors are usually around 1" smaller, measured DIAGONALLY (not dialog) from corner to corner of the visible area - but actual image sizes vary from maker to maker. LCD sizes are normally quoted as the actual visible size.

If you check the specs for a given monitor they will normally also give you the size of the viewable area.  This is the portion of the tube that you see.  Actual image size varies according to monitor manufacture, quality, graphics card and user selectable settings. I think this pretty well answers your question, if not post again.  If you want additional information on types and suitability of monitors let me know..  Have fun.
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sorry about that, didn't see road's comment when i answered....
victorlongAuthor Commented:
Adjusted points from 40 to 45
victorlongAuthor Commented:
Hi Road Warrior,

Thank you.

I have just tried to check my screen by using your formular....but don't know my screen is 14", 15" or 17"....:-)
what are the make and model of your monitor?

If you measure the display glass area diagonally and add 1", you will get the "adverstised" size.

If you measure 14", it's a 15" display.

This is a deceptive practice that has been going on since the beginning of television manufacture and marketing.

Got a 27" diagonal TV?  Measure it, it will be 26" actual.
victorlongAuthor Commented:
To revolws:

That is
Model No D1528-LS.(13.75"VIS)

Is that means 15" creen with 13.75 visual picture?
what is the rest means?
Yes, that's what that means.

It's classified as a 15" model but Dell is saying that the usable screen size if 13.75".
victorlongAuthor Commented:
To jhance:

Thank you for your help.


victorlongAuthor Commented:
Hi experts,

I am going to give the points to RoadWarrior who post comments firstlly and that was helpfull.

I would say thank you to all the other experts for the usefull helps.

Best wishes.

hehehehhhe, waiting for road to send some of them canadian points back to the old US of A....  :-)
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