Before the projector appeared, we mainly used slide projectors. In fact, current projectors are also special slide projectors. Some scholars have shown that the development of projectors, animation, and movies are inseparable. The earliest use of light and shadow technology began in the 17th century with the "magic slide" invented by a Jesuit priest named Atanas Kosher. Later, it has become a toy and its modern name is the projector. At first, this technique was mainly used for entertainment. The story was told on a screen using the principle of light and shadow, which is somewhat similar to the shadow play of the Tang Dynasty. However, with the development of light and shadow technology, projectors were separated from movies and animations.
In 1640, a Jesuit priest named Jesus invented a slide projector called a magic lamp, but it was burned to death as a pagan in a short time. In 1654, German Jewish Kishore first noted down the invention of the slide projector. At first, the shell of the slide projector was knocked into a square box with an iron sheet. At the top of the box was an exhaust pipe similar to a chimney. In front of it was a cylinder. A sliding convex lens was used to form a simple lens. Between the lens and the iron suitcase was a panel with an adjustable focal length. The light source in the box was candlelight. When in use, the slide projector is placed in a black room, the slide is inserted into a slot behind the convex lens. Then light the candle, the light sources are reflected and converged by the reflector, and a light column is formed by the transparent picture and the lens to be reflected on the wall curtain.
The industrial production of slide projectors began in 1845. The light source was changed from candles at the beginning, from shotguns to guns to oil lamps, to steam lamps, and finally to electric light sources. In order to improve the quality and brightness of the picture, a concave reflector was installed behind the light source. The increase of the light source increased the temperature of the cabinet. In order to dissipate heat, and exhaust heat dissipation structure was additionally installed in the slide projector. The film delivery was also been changed to automatic. The earliest slides were made of glass and were drawn manually. In the middle of the 19th century, after the invention of celluloid film in the United States, slides began to be produced by photographic transfer. The slide projector widely used today was developed and improved on the basis of the slide projector in the 19th century.
In 1989, Epson and Sony had the core technology of liquid crystal panel. In the same year, Epson's VPL-2000, the world's first liquid crystal projector, was born. From the initial projection technology CRT to LCD, through the breakthrough and development of technology DLP and LCOS, it is not difficult to see the gradual improvement of projection technology.
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