In all LCDs, the liquid crystal is sandwiched between 2 pieces of glass or transparent
plastic called substrates. Transparent electrode patterns are then made by applying
a layer of indium tin oxide to the glass and using a photolithography or silkscreening
process to produce the pattern.
What is LCD and how it works:
A liquid crystal display or LCD draws its definition from its name itself. It is
combination of two states of matter, the solid and the liquid. LCD uses a liquid
crystal to produce a visible image. LCD's technologies allow displays to be much
thinner when compared to cathode ray tube (CRT) technology.
Two general types of LCDs:
Passive matrix, and the active matrix (AMLCDs). Active matrix displays use transistors
behind each pixel to boost the image. The manufacturing process for AMLCDs, however,
is much trickier than that for passive matrix LCDs. As many as 50 percent of those
made must now be thrown out because of imperfections. One imperfection is enough to
ruin an AMLCD. This makes them very expensive to manufacture.
In the Array process, the glass substrates go through clean washing process, coating
process, photolithography process, etching process, and removing process several times.
The washing process is performed to get rid of the particles from the surface of the
glass substrate. The methods of washing process are as following; washing with chemical,
washing with ultraviolet rays, washing with pure water, and others, it will be selected
by the most suitable washing method according to the condition of the glass substrate
The manufacturer makes a metal layer for wiring or electrode by sputtering method,
and makes a semi-conductor or insulating layer by CVD method. The photolithography
process consists of photoresist coating process, exposure process, and developing
Phot Resist Coating:
In the photoresist coating process, coating the photo resist uniformly onto the
glass substrate which is already has metal layer. In the exposure process, applied
the mask pattern onto the photo resist coated glass substrate by the ultraviolet ray.
Ultra High Accuracy:
In the developing process, removing the photoresist coating areas that are not needed
by the developing solution. It must be formed the ultra high accuracy pattern onto
the glass substrate without a defect in a several microns meter unit.
In the cell process, the alignment of liquid crystal and injection of the liquid crystal
materials between the color filter coated glass substrate and the transparent electrode
patterns coated glass substrate are processed, and the liquid crystal materials are
sealed between the glass substrates.
These processes are important because it affects the display quality of the LCD.
The manufacturer selects the liquid crystal mode from TN, VA, IPS, and so on,
according to the use, for example TV, mobile, etc. Therefore, according to the
each mode, the optimization of the alignment process is necessary.
Furthermore, according to the ultra high accuracy of the pixel of the LCD these
days, the alignment technology has been progressing.
Note: This is the basic information only. If you
want to start independently, Please have practical experience, then have a clear document
for the process. Get trade licenses from local authorities. Then you will be successfull.
Wishing you all the best,