Page 150 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

1 Passive Displays:

Passive displays are widely used with segmented digits and characters for small readouts in devices such as
calculators, printers and remote controls, many of which are monochrome or have only a few colors. Passive
monochrome and color graphics displays were used in the first laptops, and they are still used as an alternative
to active matrix.
2 Active-Matrix Displays (TFTs):
Unlike passive matrix LCDs, active matrix displays have a transistor at each red, green and blue subpixel that
keeps them at the desired intensity until that row is addressed in the next frame.
Active-matrix screens are sharper and have more contrast than passive matrix displays, and their faster response
times eliminate sub-margining. In addition, they are very bright indoors because they use a back light and HDTV
sets on the market.
Active matrix is the only type of LCD on laptops. It is called a Thin Film Transistor (TFT) LCD because a thin layer
of transistor is deposited on the back of the screen, and they use TN liquid crystal with a 90° twist.
Scrolling Display
In computer displays, film making, television production, scrolling is sliding text, images or video across a monitor
or display, vertically or horizontally.
Scrolling may take place in discrete increments (perhaps one or a few lines of text at a time), or continuously
(smooth scrolling). Frame rate is the speed at which an entire image is redisplayed.

It is related to scrolling in that changes to text and image position can only happen as often as the image can
be redisplayed. When frame rate is a limiting factor, one smooth scrolling technique is to blur images during
movement.
Components of Scrolling Display
Scrolling display boards are the most attractive display boards. They are widely used in public transport vehicles,
information boards in railway stations, airports, advertisements, etc.
These are commonly made of LCDs and are usually connected to a computer or a simple micro controller which
can send the data to the screen. The micro controller can send data to the screen using its serial port. The data
could be saved in the me an OPPO A9 troller itself or it is received from a PC.

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CITS : E & H - Electronics Mechanic - Lesson 77 - 83