At present, LED display screen is widely used in various performing arts venues, and the collocation of lighting is inseparable!
In the news studio, variety show and other TV related performance scenes, the first rise of large screen is as the background, replacing the traditional static background decoration in the form of spray painted light box. As an advanced information expression tool, it not only has light source, but also can display text, image, video and other information. The way of presenting information and the transformation of content are diversified. It can make the background multi-purpose, give more possibilities to the studio and stage, and even affect the style of the scene, make the scene changeable and rich, quickly respond to various needs, and shorten the production cycle of the project.
In addition to the main functions of the background, in the news studio, it is also common to use the remote control or touch screen, which can achieve more real-time interactive operation and more forms of program expression; in large variety shows and evening parties, it is also common to use the splicing screen to splice a variety of abnormal shapes, to build a variety of scene modeling, and become a part of the stage art.
In recent years, with the vigorous development of LED grid screen and glass screen, the use of transparent screen (commonly known as ice screen) has become popular in all kinds of large-scale stages. In the dark, it is like a screen curtain to decorate the stage shape. When it lights up, it becomes a floating picture in the air, and it also has a higher brightness output, compared with the commonly used front projection with “translucent” screen Transparent screen is more widely used and has higher practical value.
1、 Types and application history of large screen
Up to now, the mainstream types of large screen products are CRT, LCD, DLP, PDP, led, etc., of which CRT, LCD, DLP three kinds of display technology are based on projection technology of optical display technology, mainly with rear projection to present the picture; and LED is through the control of semiconductor LED matrix to image, each semiconductor LED unit is a light source unit, its main function is to control the LED matrix Compared with the former, the output of the light source has no excessive brightness attenuation.
In the early days, many large-scale parties and variety shows used CRT as the background instead of spray painting scenes. Many CRT screens were often used as a large screen, but it was bulky, low brightness and high energy consumption. At the end of 1990s, the technology of DLP and LCD gradually matured, and broadcast news studios began to be widely used. Both of them have excellent performance in color restoration and brightness, and can be connected to external electronic devices for remote control and interaction. At the beginning of the 21st century, LED large screen gradually began to be popular. It has the advantages of low energy consumption, long half-life of light source, strong shape variability, wide area laying range, gorgeous color, high definition of distant vision and side view, and is widely used in media industry, advertising industry, high-tech industry and other industries. In the early stage of LED application, low resolution color screens are mostly used for dance decoration; with the progress of technology, the spacing between display units is getting smaller and smaller, the single bead structure is simplified, and the optical power is getting higher and higher. High resolution LED large-scale display screen, led glass screen, and led grid transparent screen are beginning to become the mainstream.
2、 The relationship between large screen visual effect and lighting design
The large screen is the same as the lamp, which has the properties of color temperature, illumination, color rendering and so on. Although the division of labor between large screen visual effect and lighting design is usually different, it belongs to one type of work, but in the actual program recording, the relationship is very close. Controlling the relationship between the two and doing a good job in cooperation will have a huge impact on the final effect of the program.
1. Color temperature control
From a lot of practical experience, it is found that the color temperature of the light source is controlled above 3200 K when tungsten filament lamp and xenon lamp are used in the past, which makes the color restoration degree of the object very high. With the popular use of LED light source lamps and LED large screen and other cold light sources, high color temperature scenes of 5600k are also common. Large screens such as LCD and DLP are rear projection screens. In the internal structure, the light source passes through multiple refraction reflection and various color filters for imaging. The color temperature of the light source will deviate from the default parameters of power adjustment of the equipment in the final output. Therefore, it is necessary to carry out a separate color temperature calibration test just like lamps, so as to unify the two color temperatures.
2. Illumination control
LCD large screen is famous for its high brightness, while DLP is famous for its high color reproduction. However, the actual brightness of the two is 250-300 nit, which is the theoretical value. Therefore, in order to coordinate the overall picture effect of the stage, the illumination of the characters’ basic face should be controlled between 500 LX and 600 LX. In this way, the brightness ratio of the face lighting and the output lighting of the large screen is controlled at more than 2:1, the characters can be highlighted, and the large screen can achieve normal exposure, and the details of the highlight part of the large screen can be retained.
3. Light ratio control
LED large screen technology has become more and more mature, high light flux products have begun to popularize. Different from LCD and DLP, the brightness of LED large screen is already very high. The large screen mentioned above can even be used as a separate variable color light source.
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