With the help of the structures explain lcd, Electrical Engineering

Assignment Help:

Q. With the help of the structures explain LCD.

A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices.

Each pixel (picture element) consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other.

The molecules of the liquid crystal have electric charges on them. By applying small electrical charges to transparent electrodes over each pixel or subpixel, the molecules are twisted by electrostatic forces. This changes the twist of the light passing through the molecules, and allows varying degrees of light to pass (or not pass) through the polarizing filters.

Before applying an electrical charge, the liquid crystal molecules are in a relaxed state. Charges on the molecules cause these molecules to align themselves in a helical structure, or twist (the "crystal"). In some LCDs, the electrode may have a chemical surface that seeds the crystal, so it crystallizes at the needed angle. Light passing through one filter is rotated as it passes through the liquid crystal, allowing it to pass through the second polarized filter. A small amount of light is absorbed by the polarizing filters, but otherwise the entire assembly is transparent.

When an electrical charge is applied to the electrodes, the molecules of the liquid crystal align themselves parallel to the electric field, thus limiting the rotation of entering light. If the liquid crystals are completely untwisted, light passing through them will be polarized perpendicular to the second filter, and thus be completely blocked. The pixel will appear unlit. By controlling the twist of the liquid crystals in each pixel, light can be allowed to pass though in varying amounts, correspondingly illuminating the pixel.


Related Discussions:- With the help of the structures explain lcd

Show that operating point does not depend on beta, Q. Prove mathematically ...

Q. Prove mathematically that the operating point does not depend on beta, in a potential divider bias circuit ? To determine the operating point, consider the input section of

What is permeability of magnetic materials, Q. What is permeability of magn...

Q. What is permeability of magnetic material? For magnetic material media, the magnetic flux density B, expressed in tesla (T) or Wb/m 2 , and the field intensity H, expressed

Design three-bit counter using t flip-flops, (a) A universal shift regist...

(a) A universal shift register can shift in both the left-to-right and right-to-left directions, and it has parallel-load capability. Draw a circuit for such a shift register.

Calculating the force between conductors, We now have an equation for the m...

We now have an equation for the magnetic field H at a distance r from a conductor carrying a current I amps And Ampere's experiments show that the force per unit lengthbetw

Determine the range of analog output voltage, Q. For the 4-bit D/A converte...

Q. For the 4-bit D/A converter of Figure with V ref =-5 V, determine the range of analog output voltage and the smallest increment. Ans. The binary input range is from 0

Pn diode, PN Diode The current-voltage characteristics are of major ...

PN Diode The current-voltage characteristics are of major concern in the learning of semiconductor devices with light entering like a third variable in optoelectronics devic

Circuit theory ., it''s 3 assignments and each assignment have 7 questions ...

it''s 3 assignments and each assignment have 7 questions so each assignment have 1 hour when I open it I have only 1 hour to finish it I can show him or her the practice question t

Image processing, i have an assignment. please help me.

i have an assignment. please help me.

Problem of current electricity, charges of +2q and -4q are fixed a distance...

charges of +2q and -4q are fixed a distance d apart as in figure_2(a).find electric field at the point A ,B and C (b) sketch roughly the electric field lines.

Cost and profitability - proposed kpis, Cost and Profitability - Proposed K...

Cost and Profitability - Proposed KPIs  KPI  UOM  Measures   RepresentativeStandards  Aggregate Technical &  Commercial L

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd