Introduction to Twisted Nematic Liquid Crystal
Twisted Nematic Liquid Crystal (TNLC) is a type of liquid crystal display that is widely used in various electronic devices such as calculators, watches, and smartphones. It is based on the arrangement of liquid crystal molecules in a twisted structure between two glass plates. The liquid crystal molecules are aligned parallel to the glass plates, but their orientation gradually twists as they move between the plates. This twisting causes the liquid crystal to become optically active, where it can selectively block or allow light to pass through.
Working Principle of Twisted Nematic Liquid Crystal
The working principle of TNLC is based on the polarization of light passing through the liquid crystal layer. When no voltage is applied to the liquid crystal layer, the twisted nematic structure causes the polarization of light to rotate by 90 degrees, which allows it to pass through the second polarizer. However, when a voltage is applied to the liquid crystal layer, the molecules align parallel to the electric field, which untwists the structure and prevents the rotation of polarization. This causes the light to be blocked by the second polarizer, resulting in a dark pixel.
Advantages and Disadvantages of TN LCDs
The advantages of TNLCs include their low power consumption, high contrast ratio, and fast response time. They are also relatively inexpensive to produce, making them a popular choice for many applications. However, TNLCs have some disadvantages, such as limited viewing angles, poor color reproduction, and susceptibility to temperature changes. They are also prone to distortion when pressure is applied to the screen.
Example Applications of Twisted Nematic Liquid Crystal
TNLCs can be found in a wide range of electronic devices, including digital calculators, wristwatches, and mobile phones. They are also commonly used in small-sized displays, such as those found in car dashboards, medical equipment, and home appliances. Additionally, TNLCs are used in some virtual reality headsets and gaming displays due to their fast response time and low latency.