Are laptop screens only capable of showing 262144 colors?

Archived from groups: comp.sys.laptops (More info?)

Hi,

Some (or most or all?) laptop screens are apparently only capable of
18-bit color; six bits for R, G and B giving a total of 262144 colors.

International Display Technology (IDTech) make LCD panels. Looking at
their products page (http://www.idtech.co.jp/en/products/index.html),
all their laptop-size panels from 1024x768 (XGA) to 2560x1536 (QXGA)
only support 262144 colors. The larger panels (18.1" and up) do show
full 24-bit.

That was news to me - I haven't read laptop manufacturers' spec sheets
saying anything other than 16M colors. E.g. NEC claims its Versa P700
(with QXGA LCD panel probably made by IDTech) has "2048x1536
resolution with up to 16.7 million colours" at
http://www.nec-online.co.uk/produc [...] roDis=1260

Are all laptop screens like this? Does the LCD controller or graphics
hardware dither the image to give the illusion of more than 262K
colors?


-- Mark