Falling prices and larger screen sizes mean the market for LCD screens is growing. Today it accounts for five per cent of the world display screen market. According to Stanford Resources, that market share will increase by ten per cent over the next four years. Nokia Display Products, which manufactures both CRT and LCD screens, has compared these two types of screen.

PICTURE QUALITY
The LCD screen's design gives it a great advantage regarding picture quality.

Flicker
The image on a CRT screen must be updated continuously. Flicker occurs if updating is not sufficiently fast. An LCD screen requires no updating provided the image does not change. When updating is required, an LCD screen can update up to one thousand times faster than a CRT screen.

Sharpness
The image on a TFT LCD screen is composed of many millions of dots, each of which is controlled by its own transistor. Sharpness is therefore much better than with a CRT screen where the beam of light does not hit the dots with the same precision.

Viewing angle
The CRT screen is superior with regard to viewing angle. If you view an LCD screen from the side, only a small part of the light reaches the eye, which means brightness and contrast are impaired. However, the viewing angle for LCD screens has been improved considerably. Nokia's screens have a viewing angle up to 160 degrees, both horizontally and vertically, which is almost as good as a CRT screen.

The eyes
The LCD screen is also superior regarding straight lines, convergence, brightness and contrast, which means it is more restful for the eyes to work with.

SIZE/IMAGE AREA
Normally a large CRT screen is 21 inch, while a large LCD screen is 18 inch. This is because the active image area of a CRT screen is 1-2 inches smaller than an LCD screen. A 13.3 inch LCD screen corresponds approximately to a 15 inch CRT screen.

The requirement for ever larger display screens creates a problem for both CRT and LCD technologies. A CRT screen is large, heavy and cumbersome (the largest CRT screen manufactured is 42 inch and weighs 142 kg). The bigger the image area, the deeper and heavier the screen. An LCD screen takes only a fraction of the CRT screen's space and weighs considerably less. The LCD screen's problem is the large number of transistors required. The number of transistors increases with the size of the screen. A screen with 1024 x 768 dots requires 2,259 transistors, and the picture quality deteriorates if a small number of them become faulty.

MAGNETIC FIELDS
CRT screens are affected by external magnetic fields, which can mean the image becomes unstable. An LCD screen, on the other hand, is completely unaffected by external magnetic fields and has no magnetic or static emissions.


Nokia Display Products is part of the international Nokia Group company.

For further information please contact:
Monika Gustavsson, PR and Marketing Manager
Nokia Display Products
Box 1113
164 22 Kista
Sweden
Tel: +46 (0)8-793 84 30
Fax: +46 (0)8-793 84 41
http://www.nokia.se

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