1000W searchlight astigmatism effect
By means of a mirror or lens, a beam of light is concentrated in a very small solid angle so as to obtain a luminaire with a greater light intensity. According to the international Illumination Committee, the searchlight is the light of the half peak angle of the outgoing beam (the angle between the maximum intensity and the maximum intensity of the light at one plane through the maximum luminous intensity) less than 2 degrees (50% degrees).
Modern searchlights are mainly used for ship navigation (such as ship searchlights) and signal signs. With the shortening of lighting distance, the searchlight will develop to medium and small scale. Middle and small searchlights generally use halogen tungsten lamp as light source, its filament brightness is high, luminous volume is small and near point, light source can instantaneous point out, but the light source life is short. There are also ultra high pressure mercury lamp, metal halide lamp and ultra high pressure xenon lamp as the light source, it has higher arc brightness and smaller luminous body, and the starting characteristics are related to the performance of light source and trigger.
Around 1870, there was a searchlight with carbon arc light as the light source in the world. In 1877, A. mans of France invented a double spherical glass mirror, which was soon used as a reflector for searchlights. The glass mirror was replaced by a parabolic reflector around 1885. In 1892, searchlights were deployed along the English Channel for the sake of coastal defence. In 1910, the fluoride or oxide of rare earth elements was added into the arc, which greatly improved the arc brightness and increased the peak intensity of the searchlight. In 1915, the American E.A. Sperry invented the high intensity arc lamp, which was used immediately in the searchlight. In 1916, T.A. Edison invented portable battery powered searchlights. During World War I, searchlights began to load trucks and armored vehicles. In the Second World War, searchlights were used primarily to search targets for anti-aircraft guns at night.
A searchlight (Searchlighit) is a luminaire that uses a reflector or lens to focus a beam of light in a very small solid angle (usually less than 2 degrees) to obtain a stronger light.
