GIESER COMPANY TV 1979 till 2100
MECHANICAL TELEVISION 1840-1920
Several inventions were required before televison could be developed. The first was a facsimile
machine which sent images over telegraph lines then a mechanical scanner (1843) which was a metal disc
system with holes that rotated in front of an stationary picture one system for the transmission and
another for the receiver. Samples of reflected light thru the holes were syncronized with and collected
by a receiver. A selenium cell phototube was developed and used to receive the signals for these
mechanical systems. These prototypes were used for experimentation and developement very crude pictures
could be made out with this technique but it wase improved upon through 1940's. In the mid 1920's there
were several stations transmitting signals using this technique
ELECTRONIC TELEVISION 1910
The developement of an all electronic television awaited several other
discoveries . The vast improvement of radio transmission and reception of the images in 1909 was one
and another was the
vacuum tube amplifier in 1907. The receivers employed solid state rectifiers for decoding the received
signal. The rectifiers were in a 8 x 8 configuration the first 64 pixel electromechanical tv set!
The first crude moving images were transmitted in the mid 1920's
and they had a whopping 30 lines of resolution. Today's tv transmission of high definiton signals have
a vertical scan of 1080 lines and horizontal resolution of 1928 pixels.
By 1932 a system with a mechanical scanner a resolution of 240 scan lines was acheived and the
future of commercial televison was inevitable just a matter of time. A patent was awarded in
1925 to an American inventor Charles Jenkins for "Transmitting Pictures over Wireless".
Then in 1927 Bell Labs of telephone fame demonstrated the best quality pictures yet but
contunued developement was needed, one of the receivers used had a 2.5 inch screen. Today the
Dallas Cowboys have a 70x100 foot screen at the Cowboy's stadium. Electromechanical tv developements expanded
after the invention of the vaccum tube and the use of it as a signal amplifier (1907). By the 1920,s motion
was introduced with moving silhouettes. Through
the following years improvements were made in all fields of tv developement, in broadcast quality
with the ever increasing line resolution, the signal quality,better vaccum tube design and the
developement of the cathode ray tube for both cameras and tv receivers and in 1941 RCA developed
a system with a 525 line system that became the standard at that time for the United States.
COLOR TELEVISION 1928
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Color television was envisioned even while black and white television was being developed as
far back as 1897 but was not demonstrated until 1928 by Scotsman John Baird with the world's first
color broadcast in 1938 in London. It took collaboration of many countries and inventors to
develope both black&white and color televison over the years as noted by Mexican inventor Guillermo
Camarera from 1931 with a system called "telectroescopia at first" and ended up with a patent in
1940 (ref 98). As with black and white the first demonstration of tv color tv using a
mechanical/electronical system in 1939 by CBS. The first all electronic color tv was
demonstrated in 1953 but do to cost and availability of color prgrams it wasn't until the 1960's
that color tv became a household item and 1972 was the first year all USA broadcast network's showed
prime time color programming tv and the year that color tv sales surpassed the sale of black and
white tv. The FCC which controlled tv frequencies use and specifications set the vertical frame rate
at 60 cycles per second and the horizontal scan rate of 425 lines pre second.
PROJECTION TELEVISION-PROJ TV
The next advancement in televison was the large screen projection sets from 40 to 80 inches in
size and was popular from the 1970s through 2010s,it is still in use today. These were monsters
comparted
to todays large flat screen tvs and weighed up to 300 pounds. There were as many as seven different
types of rear projection tvs. Describing just a few, the first type (1) is the cathode ray tube (CRT).
It had three cathode ray tubes generally 9 inches in size. One for each basic tv color, red, green
and blue. The color information in the broadcast signal including briteness was separated into the
three basic color images, then aligned into a single image, projected onto a mirror and reflected onto
the inside of the front screen. The major problem with these projection sets was in the three color
image alignment system call the color convergence. Many sets required replacement or convergence
(alignment) of the integrated circuits (ICs) once or twice during their lifetime. This was a
tedious alignment required realign the three colors. The second type (2) discussed is a liquid crystal
projector (DLP) with a digital micromirror device (DMD) with very small mirrors in it (micdromirrors).
There is one micromirror for each pixel in the image and these mirorros control briteness. Since the
image has 1080 vertical and 1928 horizontal pixels there are 1080 times 1928 or over 2 million mirrors
in the DMDD chip.
PLASMA TELEVISION
Plasma television technology was developed in 1936 by a Hungarian inventor. (The process consists of
three cells of ionized gas which conprised one pixel. The plasma gas in each cell designed for each
of the three primary colors red,green and blue. For some 50 years plasma displays and tvs were devleped and
used for various purposes such as commerical use,gambling casino displays and business board rooms. However
it wasn't until 1994 when plasma televisions became economical enough to be sold on the consumer marketplace.
plama tvs use a lot of energy and dissapate a lot of energy in the form of heat.
HIGH DEFINITION TV (HDTV)
The next big jump in tv evolution was the developement of digital tv begun in the 1990's and
the United States adapted the current ATV standard which the FCC declared would not be based on the old
analog signal format but a new high definition television (HDTV) standard. Several proposals were
presented but Zenith Radio Corporation's Compressed Signal Prosses was selected. Among the other 2
specifications were a horizontal scan rate of 1080 lines per frame and 1928 pixels per scan or line.
LIGHT EMITTING DIODE (LED) TV
Light emitting diode tv came out about 1995 and were much superior in performance to the LCD tvs. They
were made similar to the LCD tvs except they had a back light made of light emmitting diodes (LED) and had a
smaller,lower voltage/wattage power supply. The contrast ratio was greater x to y and the off axis viewing
angle of about 60 degrees.
LIQUID CRYSTAL DISPLAY (LCD) TV
Liquid crystal display tv was sold commerially beginning about 1999 but it wasn't until 2007 that
there were more LCD tvs sold than CRT and Projection tvs. Screen sizes now range from 12 to 70 inches.
The LCD panels on these tvs are made of red, green and blue (RGB) liquid crystal cells that are activated
by the RGB video signals to produce the color images but the panels are illuminated by cold cathode
flourescent tubes (CCFT) behind them. These are miniature tubes similar to those 4 to 8 foot lights used
in homes and commerical buildings. By getting rid of the bulky cathode ray tubes the width of the tvs
are now in the order of 3 to 5 inches depending on the screen size. One of the main drawbacks on these
tvs is that a true black color cannot be produced because the CCFTs cannot be turned off completely and
there is always a slight color, ever so slight in the black areas. This meant the tvs had a poor contrast
which is the ratio of black to white in the area of x to y. They also had a poor off axis viewing angle
of about 30 degrees.
3D TELEVISION-3DTV
3D or 3 dimentional tv was the next fad that the manufacturers began pushing along with the infamous 3D
cardboard glasses. 3d tvs were popular for only a few years and peaked about 2010. Anyone born before 1960 and was
old enough should remember one of the first 3d movies, The Pit and The Pendulum with actor (xxxxx) you will
remember ducking as the pendulum with the axe head attached swinging into the audience. The 3d effect is
produce by tricking you brain into thinking it is 3 dimensional and is produced by projection different images
to each eye. There are several ways to do this including one that did not require glasses however do to cost,
occasional headache, or uncomfortable glasses they did not become very popular and are not produced anymore.
4K TELEVISION (4K UHD)
4K ultra high definition tv was introduced about 2013 it is a signal process that that is transmitted or
recorded which procuces approximatley 4 times the current pixel content of 1920 vertical by 1080 horizontal
line pixels. The new 4k picture will have 3840 vertical and 2160 horizontal pixels. The total number of pixels
in a frame the old HD format is 1940x1080=2.1 million pixels and for the new UHD format 3840x2160=8.29 million
pixels this rounds off to about 4 times more pixels per tv frame. Well enough math but that's where the 4k
comes from in case anyone asks. By the way a frame would be just one still picture frozen on the tv at a time
like a cell from a movie reel. Anyway that is all the 4K TV is about just the increase in picture resolution.
The only draw back at the time is that there is not a whole lot of video source material formatted in UHD yet,
but it will be increasing as time goes by.
ORGANIC LIGHT EMITTING DIODE TV (OLED)
Organic light emmiting diode (OLED) tv technology was developed in the 1980's? and became viable to use
for television around 2000,however they were incorporated with televisons about 10 years later. There is no
rear back light on this tv as with the LCD and LED tvs because There is no rear back light on this tv as with
the LCD and LED tvs because the QD
semiconductors are
electroluminescent elements and light up on their own when swithced on by the video signals. the OLED tvs have a
display screen assembly
about 5mm thick a third of the LCD screen thickness. the display screen
consists of the rear OLED thin film transistor layer, a screen disfuser and the clear front protection screen.
There is no rear back light on this tv as with the LCD and LED tvs because the QD semiconductors are
electroluminescent elements and light up on their own when swithced on by the video signals.
When first developed the
life time of the oled's was several thousand hours but have increased by many factors since. Also the contrast
of these tvs is many times greater than LCD AND LED since when the oleds are switched off and the screen
is completely black, not so with LCD/LED tvs that have back lights on to some degree all the time.
QUANTUM DOT TELEVISION (QDTV)
Quantum dot tv is very similar to OLED tv the main differences is that the electroluminescent material is
nano crystals that can be manufactured with a given wavelength not organic as OLED implies and the crystals are
smaller than the OLED. There is no rear back light on this tv either as with the LCD and LED tvs because the QD
semiconductors are
electroluminescent elements and light up on their own when swithced on by the video signals.
diodes. The color authenticity is also superior to LCD AND LED technology because on the single color wavelength
which does not
require modification or filtering as with LCD AND LED.
HOLOGRAPHIC TV (HGTV)
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