LED is the abbreviation for Light-Emitting Diode, an all-solid, cool illuminant that is small in size and light-weighted. LED has a wide range of applications, such as surtitles display unit in theatre and large outdoor TV screen. The LED video screen traversing the stage in insen is an example of the latter.
The LED video screen consists of several dozen groups of full-coloured LED display panels, each group formed by files of individual LED units. Each unit is in turn made up of LED in three colours (red, green and blue). Each diode allows 256 intensities, resulting in a full-coloured display of over 16 million colours.
According to the common definition of luminous efficiency, LED does not have a high efficiency rate. Yet its spectrum lies almost entirely within the visible optical frequency and so its actual efficiency can be as high as 80 to 90 per cent. Therefore, in using LED technology for image display, one needs not worry about focus adjustment and projection distance. The images displayed look even more vivid than those projected from common projectors.
Controlling LED requires very low voltage and it can be done in a simple way. The artist only needs to operate a pre-configured interface to send signals via a computer to various control circuits. In so doing, he can change the colour status of each individual unit and control with ease the variation of brightness and colour on the screen, creating a great variety of dazzling images.
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The English translation appears here with permission by International Association of Theatre Critics (Hong Kong). Both this article and its original Chinese version are published in New Vision Arts Festival 2006 Critics' Guide (October 2006) by IATC(HK). The views and opinions expressed in this article are those of the author, and do not represent the stand of the presenter, the performing groups of the Festival nor the publisher.
