Lcd vs led ? | What is led ? | What is Lcd ? | Difference between lcd and led

 What is the LCD?

An LCD (short form of 'liquid crystal display') is a passive device with no lights to display text or media. Instead of its lights, LCD uses fluorescent tubes that help produce the lights and lighten the picture. The lights are always placed behind the screen panel. LCD produces the contents on the screen in the form of a dot matrix or segments. A liquid crystal filament is filled between the transparent electrodes, and the current is passed through it to energize the filaments. This eventually helps to emit visible lights.

The liquid crystal material used in LCDs is neither a liquid nor a solid; however, it consists of properties similar to the crystallized solid. Besides, the molecules are arranged in fixed patterns. But it is important to note that the molecules are not fixed in any particular shape or form. Because LCDs are comparatively thinner than casual backlit TVs, they have angle-viewing and anti-glare issues.

What is an LED?

An LED (short for 'light-emitting diode') is a subset of LCD, which technically uses liquid crystal displays. However, it differs from LCD because the LCDs use fluorescent lights while LEDs use light-emitting diodes. These diodes are usually referred to as the semiconductor light sources that produce lights when a current passes through them. This diode mechanism in LEDs produces better and sharper pictures than the general LCDs. In LEDs, the light-emitting diodes can be placed either behind the screen panel or around the edges.

Types of LCD TVs

There are 3 kinds of LCD TVs:

Flat Screen LCDs, about an inch or two thick are more expensive, but also more popular because of their sleek look and the flexible options of standing on a surface or mounting on a wall.

Front projection LCDs or projectors, which project an image onto the front of the screen. The TV itself is just a box installed anywhere in a room, which projects the image onto a flat screen hung on the wall as large as 300 inches.

Rear projection LCDs, where the image is sent from the rear of the TV to the screen in front. Rear projection LCDs are wide, heavy and only available in large sizes (60" and up).

Types of LED TVs

There are 3 types of LED TVs based on their backlighting methods:

Edge-LEDs (the most common) are positioned around the rim of the screen and use a special diffusion panel to spread the light evenly behind the screen.

Dynamic RGB LEDs: This backlighting technique allows specific areas on the screen to be dimmed.

Full-array LEDs where LEDs are arranged behind the screen as a set, but are incapable of dimming or brightening individually.

Difference 

Although the major difference between LCD and LED displays is just the backlight but it also confers a number of improvements in the LED displays which are covered in the subsequent section:

Contrast: Contrast and Black level of the LED screen is better than the LCD screens because the liquid crystals cannot stop 100% of the backlight from cold cathode backlight and hence when the black screen is to be shown on the monitor, it is not completely black. But LED screens perfectly show the black screen as there is no backlight at all.

Color accuracy: Color accuracyfor direct and edge LED displays and LCD displays are almost same but the RGB LEDs display has quite better color accuracy. There are three different types of LED monitors available based on the manner how the diodes are arranges in the monitor. These are - Direct LEDs, Edge LEDs and RGB LEDs. Both Edge and Direct LED display monitors use white diodes that are used to illuminate the LCD panel to produce the improved picture quality.

Viewing Angle: If the viewing angle of the display is much wider than thirty degrees from the center then the contrast ratio of the image is diminished in LCD. This affects the eyes while this disadvantage is overcome in LED. LEDs have a wider viewing angle, which means the image is still clear when viewed from the side.

Power: More power is consumed by the local dimming LED display than LCD. Hence it will be wise and economic to either compromise with energy bill or good quality picture. However, if LED is edge light then it will consume less power as compared to LCD with the same dimensions. Both LCD and LED displays do not have screen burn-in issue so they are considered suitable for long time screen use.

Use of Mercury: LED displays do not use mercury (used in cathode lamps in LCD backlight) so they are environment friendly.

Size: The size of Edge and RGB monitors is slightly thinner than the LCD monitors.

Price: Price becomes a major factor when comparing LCD and LED TVs. LED displays yield a higher price tag, which reflects their efficiency and the better picture quality. LED displays also allow for thinner, lighter televisions. This advantage further beats the retail price up of a television with an LCD display.

Which is better between LCD and LED?

LED and LCD are both the latest technologies, but LED has various advantages over LCD, making it better. To be specific, LED-based products (e.g., LED TVs) can run with a fluidity, providing better response time than LCD. Apart from this, LED TVs are much clearer and better in picture quality than general LCD TVs. The primary reason for the better quality picture in these TVs is the color wheel or distinct RGB (Red, Green, Blue) colored lights. This helps in producing more natural and sharper colors. That is the reason modern displays are coming with LED.