Research Paper on Liquid Crystal Display
Liquid crystal display technology has integrated itself into many facets of our daily lives. It has gradually become so commonplace that we as consumers barely even take notice. Going about our daily lives never thinking twice about how this technology came to be and what makes it possible. How many of us have digital watches? How many of us use cell phones, personal digital assistants, pagers, and compact disk players? Consumers are not concerned with how or why the displays work, just that there is a display and that it functions properly. It is intriguing to think of how electronic devices would have developed during the twentieth century had it not been for this specific type of technology. Liquid crystal displays have truly been instrumental in the progression and development of electronic devices. To understand what a liquid crystal display is we must first understand what liquid crystals are. The discovery of this type of matter and its subsequent development is what has led to the technology we use today.

The existence of liquid crystals was unknown to the world until a chance discovery by three scientists by the names of Virchow, Mettenheimer, and Valentin during the mid-nineteenth century. They discovered that the nerve fibers, which they were studying, formed a fluid substance and behaved strangely when viewed under polarized light. Concluding that this was an abnormality with the experiment they never realized that they had stumbled across a new phase of matter (Elston). Later in 1877, a scientist by the name of Otto Lehman discovered the second piece of the puzzle. At the time he was conducting experiments using polarizing microscopes to study the phase transitions of various substances. What he discovered was that a particular substance would change from a clear liquid, to a cloudy liquid before crystallizing. Yet just as the other scientists before him had done, he also came to the wrong conclusions regarding his experiment. Noting that the strange behavior he had observed was just an imperfect phase transition from liquid to crystalline (Walker).

It was not until many years later that two scientists by the names of Gatterman and Ritschke produced the first synthetic liquid crystal. This was quite an accomplishment because up until 1890 all the liquid crystalline substances that scientists had studied had been naturally occurring. Next on the discovery timeline is a scientist by the name of George Friedel. He is attributed with being the first to present us with how electric fields affect the way in which liquid crystals behave. Two brilliant German scientists, Oseen and Zocher, followed him and they helped develop a mathematical basis for the study of liquid crystals. As with any invention it had taken many years for the right technology to develop making it possible to exploit the capabilities of liquid crystals. So finally we arrive at about the middle of the twentieth century. By this time many minds in the scientific community had believed that the important characteristics of liquid crystals had been discovered, but this was to be false. Scientists from the United States, England, and the Soviet Union continued working on and studying liquid crystals, and in 1968 an American company by the name of RCA demonstrated to the world the first liquid crystal display (Elston).
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Now the term liquid crystals might seem like a contradiction, but it is not. Liquid crystals have the properties of both liquids and crystals. Like a liquid it has the ability to flow, but also like crystals, it molecules are partially lined up.

Molecules in this state retain their sense of order, but like a liquid its molecules can move around into different positions. Liquid crystals are described as being closer to a liquid state than a solid. The reason for this being, the amount of heat needed to change basic substances such as solids into liquids. To accomplish this requires a great deal of heat. Yet to turn a liquid crystal into a completely liquid form, not much heat energy is needed. Therefore it is closer to a liquid state than a solid (Tyson).

Liquid crystals are very susceptible to changes in temperature and that is why they are used in the manufacture of things such as thermometers and mood rings.

Temperature itself plays a significant role in determining what phase the liquid crystals are in. This is why of the several different phases; it is the nematic phase that makes liquid crystal displays possible. Since liquid crystals can be affected by electricity a particular nematic liquid crystal, called twisted nematics is used. Its ability to be affected and untwist depending on the amount of current applied is used as a way to control the passage of light through the crystal. This is the property that gives liquid crystals its practical and commercial uses in calculators, computers, televisions, and watches. To make the numbers and letters we see in displays, small electric voltages are applied to twisted nematic liquid crystals that are sandwiched between two layers of glass. When the current is applied it disrupts and untwists the molecules to varying degrees and this change of shape and color compared to its surroundings is what we see. For example, in calculators, electronic impulses control which parts of the display change shape and color so that they end up forming a number or letter (Tyson).

The fact that we use this technology to display and communicate information is its niche. Liquid crystal displays are the most popular medium for display applications large and small. In 2000 approximately two billion liquid crystal displays were made. The industry is estimated to presently be worth $20 billion. Try imagining civilizations thousands of years ago. To tell the time people used an hourglass or maybe a sundial. Even up to the last few centuries, the best and most accurate way of telling time was using a mechanical/analog watch. Communicating information required disposable items that you would not end up re-using. To send these items of information to another person the actual document had to travel and be delivered. Liquid crystal display technology has done away with this because it enables us to view and manipulate information however we see fit. Take for example a palm pilot. You can carry maybe fifty pages of information in the machine itself and yet we are only carrying one device with the ability to change how information is displayed (Cartilidge).

A popular market for liquid crystal displays has not only been the microcomputer market, but the personal computer market as well. Liquid crystal displays were estimated to be part of 27 million computer products in 1999. One of the main reasons behind this is because liquid crystal display monitors have started to replace the traditional cathode ray tube (CRT) monitors. Admittedly the technology is for the moment priced a bit higher than its veteran counterpart, but many consumers are seeing the benefits to using liquid crystal display monitors. The most obvious would be the difference in size. The biggest drawback to cathode ray tube monitors is that they are bulky, not to mention heavy. In comparison, liquid crystal display monitors are about one-sixth the width of cathode ray tube monitors. They come in sizes of anywhere between one to three inches, whereas cathode ray tube monitors and can be as much as twenty-four inches thick. That is a big difference when thinking about putting a display on a small desk. Liquid crystal display screens are also easier on the eyes because of their low intensity. Since liquid crystals cannot generate light of their own, most liquid crystal computer displays are backlit with fluorescent tubes. A panel behind the liquid crystal display makes sure to evenly spread out the light for the display. Next there would be the energy cost of running the monitor. Liquid crystal displays require less energy and are more efficient than cathode ray tube monitors. Though the liquid crystal displays need backlighting its power consumption is still negligible. As technology improves the costs of liquid crystal displays will come down and liquid crystal displays will eventually come to dominate the market. What is key to this happening will be advances in manufacturing techniques. The reason why liquid crystal displays are expensive is because of the high rate of rejection at manufacturing plants. About forty percent of the liquid crystal displays that come off the assembly lines are rejected because of bad transistors. The good liquid crystal displays sold to consumers must cover the costs of the bad ones as well (Kyrnin).

As far as the future of the industry is concerned it is very bright indeed. It would not be surprising if display technology one day replaced the use of paper. Electronic paper so to say, would replace printed material, leading to lower costs and less impact on the environment. There are many federal agencies as well as private sector companies committed to the continuing research of liquid crystal displays and their applications. Some of these would include the National Aeronautics and Space Administration (NASA), the Department of Energy, and the United States Navy. In the private sector, companies such as Micron Technologies, Apple Computer, Dell, IBM, and Dupont are leading the charge. Future applications of liquid crystal display technology might be in areas such as national defense, high-resolution navigation displays, displays on silicon, and projection light valves. Different uses for this technology are rapidly being discovered the technology can be seen everywhere we look. Not to mention making the information highway more accessible by providing people with virtual computer images anytime and anywhere. It will go on affecting the way we live and play key roles in the development of similar technologies and the progression of new ones (Walker).

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Display System Division, LED Program of MPT has recently won the Merck Award for Outstanding Scientific Contribution to the Display Technology for its paper entitled "Large-size LCD with Multi-touch Sensing Capability". The accolade was presented to ASTRI at the 9th International Meeting on Information Display (IMID 2009) held in Seoul, Korea from 12 to 16 October 2009. | | | Mr Ng Kwan-wah (third from left), Manager, Display System Division, MPT, receives the award on behalf of ASTRI at IMID 2009 in Seoul | | | The winning team comprising Senior Engineer Dr Zhu Xiuling; Engineers Ms Cass Sit Ka-man, Mr Mark Wei Feng and Mr Feng Yaojun; and Manager Mr Ng Kwan-wah authored the paper under the direction and supervision of Director Dr Tsai Chen-jung.The Merck Awards were introduced during the IMID 2004 by Merck Advanced Technologies Ltd to celebrate the 100th anniversary of liquid crystal display. The awards honor outstanding scientific contributions to display technologies. The winners are selected by an awards committee based upon criteria such as originality and technical significance. | | | Mr Ng posing in front of the display of the award winning paper | | |