LCD TV

Liquid Crystal Display is all about flat panel television technology. The technology of liquid crystal display has penetrated our everyday life in everyday things like wristwatches, mobile phones, calculators, computer monitors and high definition television. The use is growing rapidly and sales of LCD TV are expected to exceed 4 million in America alone.

There are some distinct advantages of LCD panels over other kinds of display technologies. They are slimmer and hardly go beyond 3.5`` in depth. These are lighter also and best of all they draw less power - only about 60% of the power consumed by plasma displays. LCD televisions do not spew electromagnetic waves that are harmful.

There are drawbacks of course - viewing angle is restricted, contrast ratio is limited and time of display response may cause concern. The biggest frown of all is caused by the price. Although it is falling but still it is considerably higher than its plasma counterpart.

LCD displays comprises mainly of sheets of polarized glass sheets - two in number. A liquid crystal solution is sandwiched between these. These liquid crystals are very specific that causes them to act as shutters that open or shut out entry of light as the need arises depending upon flow of electric current. This current passing through the liquid crystals is regulated by voltage that is applied between the glass sheets through the electrodes that are transparent. These form a network having rows on one direction of the panel and columns on the other side representing the pixels or picture elements.

What are these liquid crystals? Matter can be found in three states - solid, liquid and gas. Nevertheless there are substances that exist in a state that is neither liquid nor solid at any one point of time. The behavior of these molecules is also peculiar. They keep to their orientation like those in a solid and yet they shuffle around taking up various positions like the molecules of a liquid. Thus these liquid crystals can be termed neither solid nor liquid though they have more of an affinity for the latter - that is the liquid state.

There are various types of liquid crystals with each having its distinct properties. Those used in LCD panels are termed nematic-phase liquid crystals. The molecules are arranged in a particular fashion having distinctive pattern.

LCD display systems are of two types - passive and active matrix. The former is more complicated, produces the best pictures and consequently the price also goes up. During the manufacturing stage bad-pixels pose a serious problem. Innumerable controlling transistors are required on the glass substrata to control each sub-pixel. A typical wide screen panel will require 3.1 million transistors. Any one faulty transistor cannot be replaced and are known as dead or stuck pixels. If one is permanently off then a black spot will show and if it is on then a white spot will show. If it crosses a certain number the whole unit will have to be discarded.

It was during the early 2000`s that LCD flat panels took over the television market from the typical CRT`s. The basis of the technology is founded on the characteristics of polarized light. The thin semi liquid crystal gel trapped between two slim polarized sheets is divided into pixels.

There is hectic activity to overcome the technological difficulties to make the set affordable. So the LCD TV has to be made affordable to hit the headlines of success.

 

[Dhruv Bindhani]

The provided text offers an in-depth look into Liquid Crystal Display (LCD) technology, detailing its widespread adoption, advantages, drawbacks, fundamental working principles, and market evolution.

Ubiquity and Advantages of LCD Technology​

Liquid Crystal Display (LCD) technology has become a ubiquitous presence in modern life, extending beyond flat-panel televisions to wristwatches, mobile phones, calculators, and computer monitors.1 Its rapid growth is evident in projected sales, with LCD TVs alone expected to exceed 4 million units in America.




LCD panels offer several distinct advantages over other display technologies:

• Slim Profile: They are notably thin, rarely exceeding 3.5 inches in depth.
• Lightweight:Their lighter construction contributes to easier handling and mounting.2
  
  
• Energy Efficiency: LCD televisions consume significantly less power, approximately 60% of what plasma displays use.
• Reduced Electromagnetic Emissions:Unlike some older technologies, LCDs do not emit harmful electromagnetic waves.3
  

Drawbacks and Cost Considerations​

Despite its advantages, LCD technology also presents some limitations:

• Restricted Viewing Angle:Image quality can degrade when viewed from sharp angles.4
  
  
• Limited Contrast Ratio: The difference between the darkest and brightest parts of the image may not be as profound as in other technologies.
• Display Response Time:Some users may experience concerns regarding how quickly pixels can change state, potentially affecting fast-moving images.5
  
  
• Price: The most significant drawback highlighted is the cost. While prices are declining, LCDs remain "considerably higher than its plasma counterpart."

How LCD Technology Works​

At its core, an LCD display consists of two sheets of polarized glass with a "liquid crystal solution" sandwiched in between.6 These unique liquid crystals act as "shutters," regulating the passage of light based on the flow of electric current.7 This current is precisely controlled by voltage applied via transparent electrodes, which form a grid of rows and columns corresponding to the individual pixels (picture elements) on the display. Nematic-phase liquid crystals, characterized by their specific molecular arrangement, are the type used in LCD panels.8






The text clarifies that liquid crystals are a distinct state of matter, existing as neither true solids nor true liquids.9 Their molecules maintain orientation like solids but can shuffle positions like liquids, possessing a stronger affinity for the liquid state.10

Types of LCD Systems and Manufacturing Challenges​

LCD display systems come in two main types: passive matrix and active matrix.11 The active matrix system is described as more complex but yields superior picture quality, which also drives up its price. A significant manufacturing challenge for LCDs is the issue of "bad pixels."12 Each sub-pixel (a component of a pixel) requires an individual controlling transistor on the glass substrate. A typical wide-screen panel, for example, demands 3.1 million transistors. If even one transistor is faulty, it results in a "dead or stuck pixel" – appearing as a permanent black or white spot.13 If a certain number of these faulty pixels are present, the entire unit must be discarded, highlighting a key aspect of LCD panel production and quality control.






LCD flat panels began to dominate the television market in the early 2000s, replacing older Cathode Ray Tube (CRT) displays. The technology's foundation lies in the characteristics of polarized light, with a thin semi-liquid crystal gel divided into pixels, trapped between two slim polarized sheets.

The industry is actively engaged in overcoming current technological difficulties to make LCD sets more affordable, as price remains a crucial factor for widespread market success.