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In 1964, the american engineer George Hailmeyer created the first liquid crystal display based on the effect of dynamic scattering.
- In 1968, RCA introduced for the first time a liquid crystal monochrome display.
- In 1973, Sharp released the first LCD calculator and began to be widely used in electronic
- clocks, meters, and calculators.
- In 1983, Casio released the first portable black and white television, and in 1984 the first portable color TV, then in 1992 the first camcorder with LCD was released.
- In 1987, Sharp released the first 4-inch LCD, and in 1988, the 14-inch.
As of 2019, LG Electronics is one of the leaders in the production and sales of this type of displays in the world market..
Structurally, the displays are a thin structure of glass plates between which is placed a layer of liquid crystals. Thanks to the voltage applied to them, the crystals are arranged in a certain order, allowing light to pass through them. Depending on the magnitude of the applied voltage through the crystals passes to a different amount of light flux. The color image is directly generated by the RGB sub pixel, using the limited angular resolution of human vision.
Highlights of LCD/LED devices:
- Matrix type - determined by the technology by which the display is manufactured (IPS, VA, TN +, OLED)
- Matrix Class - According to ISO-13406-2 there are 4 classes of matrices according to the number of pixels broken.
- Resolution - The horizontal and vertical dimensions in pixels.
- Pixel size - is the distance between the centers of adjacent pixels
- Screen Aspect Ratio (Screen Format) - Aspect Ratio to Screen Height (5: 4, 4: 3, 3: 2 (15 ÷ 10), 8: 5 (16 ÷ 10), 5: 3 (15 ÷ 9), 16: 9 and more…).
- Screen size - diagonal is the physical size of a screen measured diagonally.
- Image contrast - the ratio of the brightest point of the screen to the darkest at the set backlight.
- Brightness - the amount of light emitted by the display (cd / m2).
- Response Time - The minimum time required for a single pixel to change its brightness.
- Viewing Angle - The angle at which the screen image remains unchanged (for LG products, this angle is 176 degrees).
LCD/LED Backlighting Unit
Liquid crystals cannot directly generate light but only control it. For this purpose the backlight of the display (light source) was created, the main purpose of which is to provide a uniform light flux the entire plane of the matrix and consists of the following components:
- Light source (fluorescent lamp or other light source).
- Application that provides uniform light then throughout the matrix.
- Inverter that controls the level of the brightness of the matrix.
The displays used different types of illumination (miniature incandescent lamps, fluorescent lamps of different types, separate LEDs, LED arrays). But the use of LED backlight (LED backlight) has provided the highest quality characteristics of the TV image. It differs qualitatively in its operational properties in the direction of reliability and mechanical capabilities (manufacturers got the possibility of thinner versions of products). As a result, we have: LCD technology for display production, and LED - technology for display backlight or type of light source.
LCDs typically use fluorescent or fluorescent backlight, so they have low brightness values and a high failure rate during operation. Thanks to the use of LED lighting, TV manufacturers were able to get rid of their old sores. Now products using LED technology have increased reliability, high levels of brightness, high definition and contrast, 40% more energy-intensive, environmental safety (lack of mercury in products), and generally more attractive TV sizes (products with LED structure have thinner physical screen sizes).
LCD / LED production technology is nowadays very popular and considered to be the most widespread in the world, but it is not the latest innovative development of television technology. It is increasingly being replaced by OLED technology of production, which is more advanced in quality but more valuable to the general public.
Nowadays telecommunication data display devices are changing very fast and they play an important role in everyday life. The surrounding space is surrounded by countless information devices used by humanity. We can see them almost everywhere: on phones, TVs, navigators, laptops and more. The most common type of displays are liquid crystal displays. The term LCD (liquid crystal display) informs the potential user that screen is based on liquid crystals. They were invented in 1888 by the Austrian botanist F. Reinitz and are now widely used in everyday life.