[Classification of projection screens and suitable places] Commercial projection screens
Due to the different use methods and working conditions of the screen, it can generally be classified according to the three aspects of the optical characteristics of the screen, the acoustic characteristics and the way of erection:
According to the optical characteristics of the screen surface: diffuse reflection screen; directional diffuse reflection screen; honeycomb screen; transmission screen according to the acoustic characteristics of the screen: perforated screen; non-porous screen according to the installation method: fixed screen; Mobile screen
Diffuse reflection screen: It is a common screen for showing movies and slide projections. There are cloth screens, rubber screens, plastic screens and screens coated with barium sulfate, matt paint, zinc oxide and other paints on the above surface. Its characteristic is that the surface of the screen can evenly scatter and reflect the light flow irradiated on the screen to all directions. When viewing the screen image from any different angle in front of the screen, its brightness does not change with the direction and angle. It is suitable for larger places, Suitable for the projection of black and white and color images.
Directional diffuse reflective screen: Its optical characteristic is to make the light flow irradiated on the screen more concentrated in a certain direction after reflection and redistribution. The disadvantage is that the diffusion angle is relatively small, and there are two kinds of metal screens and glass bead screens. The metal screen is coated with a layer of white metal powder, such as aluminum powder, which can reflect various colors of light, on the base of the screen. The glass bead screen is coated with a layer of white glue paint on the surface of a fibrous material, and then a layer of transparent spherical glass beads is evenly coated on the white paint.
Honeycomb screen: The honeycomb on the screen is made up of many small convex or concave mirrors or lenses with a smooth surface by molding or rolling, and arranged in a certain order. Some are made of small plates, and some are made of small concave mirrors that are pressed into a concave surface with small steel balls.
Transmissive screen: It is used for indoor screening of movies, projections, and slideshows without shading equipment. The audience can watch on the back of the screen. The brightness of the screen depends entirely on the amount of light transmitted from the back of the screen. Therefore, this screen has a large transmittance. Because the audience is on the back, it will not be disturbed and can reduce the visual fatigue of the human eyes; because the room is bright, the audience can take notes while watching. Therefore, the screen was officially used for school audio-visual teaching.
Perforated screen: A screen with many small holes evenly punched on the squinted surface. When using an ordinary screen, the speakers are generally on both sides of the screen, but in order to coordinate the sound and the action effects of the screen, the speakers are best installed in the center of the screen. However, the texture of the screen surface of ordinary screens is dense, and it is difficult to transmit sound, which affects the quality of surround sound. In order to make up for this shortcoming, perforated screens are often used in movie theaters or clubs.