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Sharp Developing LCD Screens In Almost Any Shape
jfruh writes: Traditional LCD panels are rectangular because the tiny chips that drive each pixel of the display are fitted along the edge of the glass panel on which the screen is made. But in a new breed of screens from Sharp, the chips are embedded between the pixels so that means a lot more freedom in screen shape: only one edge of the screen needs to be a straight line, which could give rise to a host of new applications.
only one edge of the screen needs to be a straight line
Take a look at the examples on this page. Notice that three sides are straight. Only one side has any variation. Could it be that the drivers for one axis must be at the edge?
As a (mostly) PCB designer, I find these TAB (tape automated bonding) attachments to the panel to be fascinating. The chips are the column and row drivers, that is, these chips have the job to drive the gates of the transistors that control each and every sub-pixel on the panel.
So your typical 1920x1080 LCD panel has 1920x3=5760 columns to drive. That's R G and B for every pixel. There are 10 such chips arranged along the top of the panel, which means each chip (about 10x3mm) has to have 576 analog outputs driven from the RSDS digital bus, itself generated from the TCON (timing controller) which receives the video in whatever format and translates it to the particular panel's needs (ie, bit depth, refresh type, etc).
Oh yeah, each LCD shutter must never have a DC potential on it for too long, so on each alternate cycle the polarity of the control signal is inverted.
This has something to do with the crystals themselves becoming "denatured" if they're in the same position too long.
Not only that, but the gate drive is non-linear and the column driver has to compensate for that, of course each type of compensation depends on the exact chemistry of the crystals used.
Anyways, if you look at the little PCB it's 1 mil thick (~0.025mm), and has hundreds of traces packed into a few mm... Not to mention the hundreds of contacts on the chip, all perfectly aligned to the PCB.
Ever wonder how the distance between the front and back panels is kept so uniform across the panel? ...
There's thousands of tiny ceramic beads in the panel to maintain the precise separation
Ahhhh yeah, this stuff is cool, amazing what we can afford to make and throw out if it doesn't work.
Mostly random stuff.