EXPLAINING PRINCIPLE WORK OF PICTURE TUBE

EXPLAINING BASICS VIDEO SIGNALBY SARBINI, S.Pd (SMK MUH 3 YOGYAKARTA)

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A. Picture tube kinds :

CRT (Cathoda Ray Tube)

LCD (Liquid Cristal Display)

PLASMA

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TECHNOLOGY CRT

Digital Intelligent Picture Enhancement (DIPE) (each incoming signal is digital).

Digital Natural Image engine atau disingkat DINe (equipped with a series of features digital image processing most up to date, including :

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Six-times Density Enhancer (Technology to improve the image density so that the high-resolution images produced become more clear)

Signal Optimizer (Technology to optimize the signal into the television tube to remove the image distortion due to the intensity signal for broadcast transmission of low).

Detail Enhancer functioned to sharpen colour limitation so that not blurred. Added with details clarity equation according to uniform in every channel. Detailed pictures are to be accurately as the original.

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Color Optimizer to present natural colourful with optimizes colour that enter.

Contrast Enhancer (this technology increases colour contrast power by expands bright colour gradation pattern and dark so that light intensity factious will be obviated and the resulting picture becomes more natural.

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STANDARD AND DISPLAY RESOLUTION

STANDARD TYPES RESOLUTION (PIXSEL)

APPLICATION

XGA (Extended Graphics Array)

1024x768 15- and 17-inch CRT monitors15-inch LCD monitors

SXGA (Super XGA) 1280x1024 15- and 17-inch CRT monitors17-and 19-inch LCD monitors

UXGA (Ultra XGA) 1600x1200 19-, 20-, 21-inch CRT monitors20-inch LCD monitors

QXGA (Quad XGA) 2048x1536 21-inch and larger CRT monitors

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STANDARD AND DISPLAY RESOLUTION

STANDARD TYPES

RESOLUTION (PIXSEL) APPLICATION

WXGA (Wide XGA)

1280x800 Wide aspect 15.4-inch laptops

LCD displays

WSXGA+ (Wide SXGA plus)

1680x1050 Wide aspect 20-inch LCD monitors

WUXGA (Wide Ultra XGA)

1920x1200 Wide aspect 22-inch and larger LCD monitors

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1. CRT (CATHODA RAY TUBE)

Cathode Ray Tube (CRT) : a containing vacuum tube a electron rifle (electron guns) and a heater element, functioned to speed up and turn electron beam.

Parts of the CRT color

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Cathode rays : a secretory electron beam from a cathode heater (heater) that resides in in vacuum tube, where does this electron beam will be pulled to anoda because the potential is high among katode and anoda, (voltage is generally in the orde Kilo volt)

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PARTS AND WORK PRINCIPLE CRT COLOURED

1. Electron guns

2. Electron beams

3. Focusing coils

4. Deflection coils

5. Anode

6. Mask

7. Phosphor layers

8. Close-up of the phosphor

Parts CRT colour

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The screen has a number of phosphorus that will be fluorescent when exposed to fire electrons produced by electron gun.

This electron beam be turned by magnetic field that controlled by vertical spool and horizontal (spool yoke).

Magnified view of a shadow mask color CRT

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Electron at shoot off and will hit dots pospor will produce bright light and can be seen in the screen.

Tube also have mask color, to place pospor's dots so correct electron beams.

There 3 circles pospor that is

red, blue and green. when described based on sequence the colour, so seen to like picture.

Magnified view of an aperture grille color CRT

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Electron beam source electron rifle, produce a electron current passes emisi-termion, and centripetal be a little dots.

Electron gun

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5. Plasma

Plasma is one of the alternative technology.

To display colour picture, technology plasma use combination pospor red, green, and blue.

Example of television display plasma

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Principle of work

Plasma give load to pokes containing of neon gas and xeon that reside in between two glass panels.

Plasma consist of one million tube fluorescent measure very little.

Composition plasma display panel

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When does tube fluorescent given load, neon gas and xeon will take ultraviolet photon.

Then photon will thresh pospor that shine colour light.

This light combination will produce picture on television as we shall see.

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Troubleshoot Plasma

Problem that appear screen plasma centre around performance pospor that take outside light:

Performance pospor will decreased along walk it time. If performance pospor decreased, so light that taked moment pospor threshed photon, on the wane and dull.

Contrast ratio will experience depreciation as big as 50 percents during use 4-5 year.

While for aspect brightness (bright ratio), several producers claimed, depreciation as big as 50 percents, new will happen after use during 60.000 clock (15 year normal use).

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Layer construction in plasma

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Grid formed by two electrodes

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3. LCD

TV LCD has contrast ratio begins from 400: 1 up to 800: 1.

TV plasma begin from 600: 1 until most sophisticated has ability 1.500: 1.

In TV LCD, screen is illumined by rearlamps so that relative not influenced dazzed because light reflection and give soft modulation pictures and bright even in room that shine bright or near where does sunshine enter.

TV LCD is light and movable easily, one that matter can almost place where just that is wanted the user.

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Parts of LCD and the function :

Vertical filter film to polarization when enter light.

Glass substrate with ITO (Indium Tin Oxide) electrodes to will determine (to form) dark element that appear when LCD be lighted or deaden.

LCD‘s display part

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Twisted nematic liquid crystals.

Glass substrate with common electrode film (ITO) is equiped horizontal ridges so that be a line with horizontal filter

Horizontal film filter to blocks and get away light. picture 5-17. LCD’s display parts

Reflective surface to bounce back to return light forwards. (in backlit LCD, layer this replaced with light source)