[Three most noteworthy principles for purchasing 'projection screens'] Projection screens

A good projection effect is determined by many factors. Usually, many people just pay attention to the purchase of the projector and neglect the screen. The ending is that the projector is expensive and attracts the attention of users, and the other is the projection screen manufacturer. The publicity is not enough. In fact, if you want to get a good presentation effect, the choice of projection screen cannot be ignored, otherwise your presentation effect will be greatly reduced. Let's talk about the three most important principles to consider when choosing a suitable projection screen:
1. Choose different sizes according to different spaces
　　 Even if the projection screen is made of the same material, its processing and processing methods are different, and its physical indicators will still have a certain gap. Therefore, before purchasing a projection screen, the user should first determine the appropriate size according to the size of the projector's use of space Screen size.
　　 The size of the screen is defined by its diagonal size. Generally, the aspect ratio of the video image is 4:3, such as a 72-inch screen. According to the Pythagorean theorem, the screen size can be quickly obtained The width is 1.5m and the height is 1.1m. At present, the specifications and sizes of projection screens on the market are 72, 100, 120, 150 inches, etc. Among them, 72-inch projection screens are the mainstream products in the market. This size screen can be selected for general-scale projection teaching and general product demonstrations, and Screens of this size are also the lowest in price, and usually those with a projection space of less than 100m2 can be used for this type of screen. If the projection space area is more than 100m2, you can consider using a projection screen of 72 inches or more. If the projection screen is used in a large conference hall, then the user should choose a larger projection screen according to the number of audiences, the seating situation and the projection area ( Such as a projection screen with a width of 4 to 8 meters), of course, the larger the screen size, the higher its price.
　　 In addition, if the installation of the same size screen is slightly improved, the effect is also very significant. When the screen is installed, it is at a small angle to the vertical surface, and the reflected light is controlled to hit the center of the auditorium. The viewing angle of the rear row will be reduced accordingly, and the brightness of the auditorium will be significantly improved. Of course, due to the change in the image distance, the image will be distorted. At this time, the keystone correction function of the projector can be used to correct it.
　　 In short, the principle of selecting the screen size is to choose the screen that suits the audience rather than the screen that fits the projector, which means that the audience's visual experience should be put first.
2, choose different materials for different applications
　　 On the surface, the appearance color of the projection screen is white, there is no difference, in fact, screens of different materials have different characteristics. From the material point of view, projection screens can be divided into glass bead screens, metal screens, and embossed plastic screens. Metal screens are mainly used in large-screen stereoscopic projection systems because this screen has the characteristics of wide-screen viewing angle, standard gain, soft light, less fatigue for the audience, beautiful appearance, easy installation, fire and mildew, and allows users to clean at any time. Glass bead screens are mainly used in conference projection demonstration systems, because this type of screen has high reverse gain and wide viewing angles, which is particularly suitable for product display. The embossed plastic screen has relatively low gain and limited light reflection ability, but its viewing angle is very wide, which can almost reach 180°, so the embossed plastic screen is especially suitable for ordinary classroom teaching.
3. Choose different functions for different purposes
　　Different users have different purposes and requirements for using the projector. To achieve the best projection effect, you must first ensure that the selected screen matches the function of the projector. Before choosing a screen, users need to be clear about the purpose of purchasing the projector. For example, if you want to use the projection screen in a multi-functional presentation hall, the screen you choose is best to carry and place. You might as well choose a tripod or wall-mounted projection screen so that you can store it away at any time after the screen is used up.
　　 If the screen is used in an audio-visual classroom, you should choose a fixed screen type, because the usage rate of projection screens in an audio-visual classroom is relatively high, and it is obviously troublesome to frequently move the screen or roll the screen up and down. If you are a user who frequently conducts tour demonstrations, a portable screen is the best choice.
　　 If the user has better economic conditions, he can choose an automatic retractable screen. This type of retractable screen can be divided into manual retractable and electric retractable. I think it is better to choose the electric type if the funds allow, because the electric retractable screen uses a motor to control the screen expansion , The length of the screen can be automatically arbitrarily positioned, and this screen can also be used as a part of the central control system for remote operation. Manually retractable screens, users can only use manual methods to open or retract, this kind of screen is relatively cheap, the operation is also very simple, it is an economical and practical choice for ordinary users with low requirements. Now there is a new type of manual screen, which uses a self-locking device, the user can arbitrarily locate the position of the screen, it is very convenient to use.
　　 In addition, projection screens can generally be divided into reflective and transmissive types in terms of function; reflective type is used for front projection, transmissive type is used for rear projection; front projection screens are further divided into flat screens and curved screens. The flat screen requires weak ambient light, and the ability of this screen to reflect light is poor. Therefore, it is only suitable for ordinary teaching display. Because the arc-shaped screen has a strong ability to reflect light and has low requirements for ambient light, it is more suitable for higher projection requirements, such as home theater systems, large conference demonstration centers, etc.