The liquid crystal is in the most everyday objects: calculators, watches, electronic games, personal computers, televisions. In almost all homes there are several computers that have display devices, the well-known displays, whose active components are liquid crystal. We can also find them on information panels in airports or stations, windows that change from translucent to opaque, on photocopiers or projectors. They are also found in places as disparate as cosmetics , temperature gauges, or fire or impact resistant fabrics .
Summary
[ hide ]
- 1 Definition
- 2 Classification
- 3 History
- 4 Applications
- 1 In medicine
- 2 In technology
- 3 Other applications
- 5 Sources
Definition
The term “crystal” refers to materials that have that kind of ordered structure, but in a liquid crystal , as in a normal liquid , the position of the molecules is not exactly very ordered. So what makes it different from an ordinary liquid is the elongated and thin shape of its molecules. Although the position of the molecules is random, their orientation can be aligned with each other in a pattern. That is what creates the ordered structure, as in solids, of a liquid crystal.
Classification
- nematics
- smetic
- cholesteric
Most of these respond easily to electric fields and thus exhibit different optical properties depending on the presence or absence of the field.
History
In 1888, the Austrian botanist Friedrich Reinitzer, during his industrial research on the reactions of cholesteryl benzoate, realized that at 145.5 degrees Celsius this substance did not change into a clear liquid, but into a cloudy fluid. And when heated to 178.5 degrees it turned to clear liquid. This proved that this substance had two melting points. In 1889 the physicist Otto Lehmann discovered that, in the opaque phase, cholesteryl benzoate had areas of crystalline molecular structure. He named them liquid crystals. A year later, in 1889, the German physicist Otto Lehmann discovered that, in the opaque phase, cholesteryl benzoate had areas of crystalline molecular structure. It was he who called them “liquid crystals.” Later, in 1904, The Merck company offered Lehmann the first substances with high purity crystalline liquid properties. In the 1920s they were already accepted in the scientific community and the three types of liquid crystals (nematic, smectic and cholesteric) were established. However, in the 1930s the interest in liquid crystals declined because there were no possible technological uses for these substances. In the 1960s, the attraction for liquid crystals reappeared and they began to be used as an indicator of temperature, in thermography and medicine, and later also used in fashion and cosmetics. Thus, in 1968, Merck began research on liquid crystals to verify its technical application in monitors. In 1976, the company started to patent different liquid crystal mixtures, and in 1980 he developed the VIP Display, the ‘independent vision panel’, the basis for all active matrices of LCD flat panel displays. In 1995- Merck and Hitachi cooperated in developing a new technology for LCD monitors based on a patent filed in 1990 in Germany, which was purchased by Merck in 1994. In 2003, Merck won the German Future of Technology Award. of Liquid Crystals that made flat screen televisions possible Merck took over the tire business of Hoffmann- La Roche Ltd in 1996. A year later, together with Fujitsu, developed an LCD video monitor based on Vertical Alignment (VA) technology. In 2003, Merck won the German Future Prize for Liquid Crystal technology that made flat-screen televisions possible. In 2008,
Applications
In medicine
One of the first applications of liquid crystals was in medicine , as an analytical tool to measure temperature variations . Since then they have been applied in the health sciences , thanks to their properties and characteristics, both physical and chemical. Thus they are useful in oral and skin thermometry, gynecology , neurology , oncology and pediatrics , among others.
In technology
The rapid development of visual technology has accompanied computer advances, since without such display screens we could not benefit from the capabilities of the computer . Thus, the screens allow us to visualize the information that the computers supply us. But, in addition to being useful in computers, the screens are mounted on other devices such as audio equipment, household appliances and car equipment, among others. Liquid crystal displays have played a key role in this development and it seems that they will play an even bigger role in the future. The displays can be built using different technologies, among others, the LCD or OLED technology.
Other apps
Liquid crystals are also used in photovoltaic materials (to simplify processes and fix solar cells more efficiently while respecting the environment ); in semiconductor materials for solar cells (solar cells made of conductive plastic are distinguished from organic photovoltaics (OPV): they are not only cheaper and brighter, but they are also more flexible and versatile than their silicone predecessors ); and in security and identification materials (printable conductive polymers for the manufacture of RFID chips.
