CNT TV - The Evolution of TV Display Processes
The evolution of the television – and the technology utilized to obtain the brightest and best picture – has grown exponentially since the mid-20th century.
At the beginning of the television era, pictures were shown via cathode ray tubes (CRT). Cathode rays were produced in vacuum sealed glass tubes, but even that process was not well developed until 1897. That was when J.J. Thompson observed that the cathode rays were composed of electrons – very small, negatively charged particles found in every atom – for which discovery he received the Nobel Prize in 1906. The original CRT’s can be illustrated by envisioning a light bulb – a filament contained in a vacuum glass tube. CRT’s inspired the development of numerous electronic devices such as the radio transistor, telephones, and first computers, as well as being used in early televisions. There were two major drawbacks to CRT’s, however. They required a lot of space, and, since they were unreliable, the tubes had to be replaced frequently.
That early TV cathode ray tube (picture tube) functioned by transmitting a stream of electrons focused into a sharp beam; the beam was then accelerated, deflected, and sent through the vacuum tube, eventually hitting a phosphor-coated screen, producing the television image. In the first color televisions, three types of phosphors, arranged in dots – red, blue, and green – were used, each emitting light transmitted by different beams which allowed a large color spectrum based on variations and combinations of the three colors. In order to provide images in motion, the screen was scanned 30 times per second by an electron beam to refresh itself. However, in order to allow a complete scan per second, the electron beam source had to be a distance away from the screen, and as the demand for larger screens grew, so did the required length of the picture tube, and thus, the depth of the television set.
Liquid crystal displays (LCD) and plasma displays were next on the horizon, and both provided flat, thin screens because they eliminated bulky tubes completely, relying on printed circuits instead. The disadvantages were restricted fields of view, low picture quality, and high cost. Over time, improvements in the technology, such as active matrix LCD and plasma displays, have rectified some of these issues with a higher refresh time, resulting in better picture quality.
Now, for the last ten years, the new direction in television technology is a direct result of research related to nanotechnology. In the not so distant future, televisions using carbon nanotubes as the electron source illuminating each individual pixel, will have thin screens, superior picture quality, cost less to operate, and can be manufactured at a greatly reduced cost.
Nanotubes are comprised of millions of invisible-to-the-eye carbon atoms arranged in a hexagonal pattern, and then rolled into a long thin cylinder. Each would be approximately 10nm in diameter. (For comparison, a human hair would be 100,000nm in diameter.) The nanotubes possess outstanding electrical properties, making it possible for each pixel to be illuminated by its own electron source made up of thousands of carbon nanotubes. Each of these tubes will bombard the phosphor screen like a cannon making a brighter-than-ever-before image. The resultant screens could conceivably produce pictures as bright as those from CRTs, yet still be as flat and thin as LCDs. These are known as Field Emission Display screens (FED).
Several companies are committed to research to discover the best way to use this technology and replace the larger CRT electron guns with much smaller CNT carbon nanotube electron “cannons.”In 2005, a Texas company – Applied Nanotech -- in conjunction with six Japanese electronics firms, successfully created and displayed a 25” color television.However, the current leader in this research is Samsung, who as early as November 2004, produced an experimental 38” model using CNT. More recently they have been developing a new type of backlight unit (BLU) based on a combination of cathode ray and carbon nanotube-lit LCD technology. It is predicted that this display will improve contrast ratio due to high backlight uniformity, as well as moving picture response time. Samsung is predicted to begin CNT TV production as early 2011, and will target the 46” display size. The sets should retail for approximately $1,300 per unit when they reach the market place.
A Brief History of Nanotechnology
Nanotechnology is probably the oldest “young” science in existence. It has been stated that there have been three separate eras in the evolution of nanotechnology: the era of not seeing (because it was too small); the era of understanding (when it was observed and the nanoscale came into being); and, the era of rapidly increasing understanding (where we are today). Here is a short timeline describing the progress of these eras.
- As early as 2000 years ago, ancient Romans and Greeks were using ground gold and silver mixed with glass to make objects that appeared to be different colors when viewed in various types of light.
- During the middle ages – around 1100 AD -- it is believed that carbon nanotubes and nanowires were utilized when producing Damascus Steel – the hardest material known for making swords.
- The first nanoparticles observed were gold colloid particles, seen by Faraday in 1857.
- By 1905, Einstein determined that those same particles were so small that they would never settle out of solution, but would remain suspended forever. He also declared that the particles would dance around, buffeted by molecular motion. He named this phenomenon Brownian Motion.
- In 1910 Zsigmondy continued to study gold colloid solutions where the particles were 10nm or less in diameter. He is the one who defined a nanometer as one billionth of a meter.
- The trans-electron microscope was invented in 1931, and allowed scientiststo finally see in “nanoscale.”
- By 1959, researchers were learning new ways to control this medium.
- In 1974, Norio Taniguchi coined the phrase, “Nano technology.”
- The last giant step into the Nano world occurred in 1981 with the introduction of the scanning tunnel microscope – so sensitive that man could actually “see” single atoms.
- By 1985, Carbon 60 was discovered, revealing the characteristic rod and ball (Buckeyball) construction of these structures.
- Finally, in 1991, Sumio Iijima discovered nanotubes.
- In 1993, quantum dots were discovered, when it was observed that the same light can produce different colors dependent on particle size. Emitting light from a semiconductor nanoparticle is called fluorescence, and nanoparticles with strong fluorescence are called quantum dots.
How Economically Important Are These Infintesimally Small Structures?
From l997 to 2006, investment in nanotech research jumped from less than a half billion dollars to over twelve and a half billion – but it has skyrocketed since then. What will be the outcome of all of this study? It is estimated that by 2015, over 50% of all new products introduced will involve some form of nanotechnology. It is also estimated that by then 15% of all goods produced globally will somehow be related to nanotechnology.
How Are Nanotubes And Nanodots Being Used Commercially?
Cancer Treatment: Some drugs used in the treatment of breast cancer were not effective because they could not reach the area to be treated. With the introduction of nanoparticles, they can be directed to the specific area, and are often used in women who have not reacted favorably to more traditional anti-cancer drug regimens.
Food Products:One use has been to keep cooking oil used in restaurants clean longer. Due to each carbon nano-unit’s large surface to volume ratio, the impurities filter out thus cleaning the oil for another use.
Micro-Electronics: Due to the microscopic size of nanotubes, they are the perfect resource to build advanced circuit boards, some of which are so small they can only be seen under magnification.
Odor-free Clothing: Some metal nanoparticles are antimicrobial, and since there is a large surface to volume ratio present in each, when introduced into certain fabrics, these metal ions kill the bacteria, resulting in a fabric that remains odor-free.
Pregnancy Tests: the test strip contains invisible particles that, when exposed to urine – containing hormones only present when a woman is pregnant – react to indicate pregnancy.
If These Structures Have Existed For So Long, Why Are We Just Now Starting To Use Them?
Because we finally have the equipment to see what we’ve made, and we can make them controllably and repeatedly. Therefore, we can economically produce nanoparticles in such quantities that it is now feasible to use them in product manufacturing.
Interesting Facts About Nanotubes
They are 100 times stronger than steel at only 1/6 the weight.
Conduct electricity as well as copper.
They channel heat as well as the world’s greatest conductor – the diamond.
A human hair is 100,000nm in diameter.
Glossary
CNT-FED: Carbon nanotube field emission display. Product utilizing one electron beam per pixel. Displays will be flat and thin, and will not use high amounts of energy. Picture will refresh more frequently than methods used at this time, which will eliminate smearing. One of the major benefits is that these television will be less expensive to produce, with the cost reduction passed on to the consumer. There will also be a great reduction in energy consumed to operate the sets.
CRT: Cathode Ray Tube – the early vacuum sealed tubes used in radios, television tubes including picture tubes, etc. The televisions were heavy, bulky, and extremely limited as to picture size.
HDTV: High Definition TV. Digitally broadcast media, affording clearer pictures, high resolution, full-screen graphics, interactive features, and a fuller viewing experience.
LCD: Liquid crystal displays. One of the current state-of-the art forms of image display.
These have a narrow viewing angle with black out as the range is exceeded. They also have slow refresh rates.
Nanotechnology: technology based on man made things with at least one measurement of one billionth of a meter.
Plasma Display: The other most popular method of image display. They are known for their high power consumption, tend to be less bright, have a potential for screen burn-in, and are relatively short lived. They are also somewhat high priced for the general public.
Quantum Dots: Emitting light from a semiconductor nanoparticle is called fluorescence, and nanoparticles with strong fluorescence are called quantum dots.
Quantum Mechanics: The study and use of nanotube technology.
Scales:- Macro – things we can see, with the human eye or with the help of an optical microscope.
- Micro – things that can be seen with the help of an electron microscope.
- Nano – things that can only be observed by using an atomic force field emitting microscope.