In a desktop I connect monitors through DVI, VGA or HDMI post that is there on motherboard of the CPU box. What interface is there in laptops? Is it the same (with different physical look and feel) Or there is any other standard for laptops ?
There are a range of interfaces used - some semi standard and some proprietary.
This page, dated February 2010, so almost 4 years old,
How do I connect my VGA card to a LCD display taken from an old laptop ?
provides some useful information.
He identifies the following typical interfaces:
Analog VGA (used in external LCD displays but not in laptops normally)
44-pin TTL parallel
TTL level clock and 8 data lines interface that has signals that match with 26 pin “VGA feature connector”
20-pin LVDS serial
Digital Video(6-bit for each color R/G/B) Sync Signal,DOTCLK, 4 pairs LVDS (used in some IBM laptop displays)
DVI (Digital Visual Interface LCD panel digital interface from DDWG, used for external LCD screen mainly)
There will be others.
Here is an example of an attempt to build an interface - 2007. Some success.
Most often, internally, its informally called LVDS, though its actually various flavours of FPD-link.
However, many newer screens are embedded display port - such as ipad retina screens. In theory you can simply break these out into standard display port connectors, and some have been building converters that work to various degree
Most laptops have a built in driver board (and an inverter for CCFL backlights), while most desktops have pretty much similar screens, other than size, with a power supply and driver board. In theory, you can buy a driver board for specific displays online, and converting LVDS screens to work on their own is fairly well documented, and it seems that its true for some eDP screens as well.