Optical display

Optical display

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  Optical display
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  ABOUT ME CONTACT INFO Tel:(+92) 322 7967172 E-Mail: [email protected] SKILLS & LANGUAGE ORIGIN LAB, VIRTUAL LAB, ENDNOTE SOFTWARE, EMATHHELP SOFTWARE , MICROSOFT OFFICE, ADBOBE (PHOTOSHOP & ILUUSTRATOR), ARDUINO SOFTWARE, AMAZON VITUAL ASSISTAN, VIDEO EDITTING, SOCIAL MEDIA ACCOUNT MANAGEMENT URDU, PUNJABI, ENGLISH, ARABIC FOUNDER UCQxAo-GBHUI2l9_LBYicsRw THE CREATOR ACADEMY thecreatorsacademyofficial thecreatorsacademyofficial The Creators Academy ABU BAKAR NATIONALITY : PAKISTAN CITY : SIALKOT, PUNJAB MARITAL STATUS : SINGLE PERSONAL PROFILE BS(HONS) PHYSICS UNIVERSITY OF SIALKOT EDUCATION SOCIAL MEDIA Abubakar Bhutta @_abubakar786 ABU BAKAR @abubakar786786 ABUBAKAR692909
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  HISTORY • Cathode raytube was discovered by Johann Hittorf in 1869 in primitive Crookes tubes. •He observe that some unknown rays were emitted from the cathode which could cast shadows on a glowing wall of tube. • In 1890, Arthur Schuster and William Crookes demonstrated cathode ray could be deflected by electric field and magnetic field respectively. In 1907 Boris Rosing used CRT in the receiving end of an experimental video signal to form a picture
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  WHAT IS CATHOD E RAY TUBE? Thecathode ray tube (CRT) is a vacuum tube containing an electron gun (a source of electrons) and a fluorescentscreen, with internal or external means to accelerate and deflect the electron beam. A fluorescent screen coated with fluorescent material to show images from X-ray.
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  How CRTS workand display? A CRT monitor contains millions of tiny red green and blue phosphorus dots that glow when struck by an electron beam that travels across the screen to create a visual image in a CRT monitor tube the cathode is a heated filament the heated filament is a vacuum created inside a glass tube the electrons are negative and the screen gives a positive charge so the screen glows
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  BASIC CATHOD RAYTUBE The CRT uses and evacuated glass envelope which is large deep heavy and relatively fragile
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  LCD Also Know asLiquid crystal display • Liquid crystal display is a thin flat panel display deice used for electronically displaying information such as text , images and moving pictures. • LCD is used in computer monitors Televisions Instrument panes, Gaming devices etc. • Polarization of light is used here to display objects.
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  Liquid crystals • Liquidcrystals are liquid chemicals in a state that has properties between those conventional liquid and solid crystals .That is a liquid crystal may flow like a liquid but its may be oriented in a crystal like way. • Liquid crystal molecules are aligned precisely when subjected to electric fields as like as in he way metal shaving line up in the filed of a magnet .When properly aligned , the liquid crystals allow light to pass through
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  The most popularliquid crystal structure is the noematic liquid crystal NLC when they are in a pneumatic face liquid crystals are a bit like a liquid their molecules can move around and shuffle paste one and other but they all point in broadly the same direction The liquid is normally transparent but if it is subjected to a strong electric field ions moves through it and disturb the well ordered crystal structure causing the liquid to polarize and hence turned off opaque the removal of the applied field along the crystal structure to the form and the material regains its transparency
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  The polarization propertyof light is used in LCD screen to switch its colored pixels of on at the back of the screen there is a bright light that shines out towards the weavers in front of this there are the millions of pixels each one made up of smaller area called Sub pixels they are colored red green or blue Each pixel has a polarizing glass filter behind it and another in front of it at 90°
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  Liquid crystals canadopt a twisted up structure and when we apply electricity to them they straighten out again this is the key how LCD display turn pixel on and off
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  • In betweenthe two polarizing filters there is a tiny twisted noematic liquid crystal that can be switched on or off electrically • When it is switched on it rotates the liquid pass through it through 90° effectively not allowing light to flow through the two polarizing filters and making the pixels look dark
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  Each pixel iscontrolled by a separate transistor that can switch it on or off many times each second . It also very the amount of light that pass hence giving different shades of red blue green to each Pixels. Which in result collectively from a image.