What Are the Different Types of Projection Screen Material?

Projection screen is a tool for displaying images and video files in movies, offices, home theaters, large conferences and other occasions. There are many specifications.

Basic Information

Chinese name: Projection screen
Foreign name: Projection screen

How it works: Use with a projector
Use: used in

How it works: Used in conjunction with a projector.

Projection screens are also called projection screens. They are generally divided into commercial screens, home screens, and engineering screens. There are many types of screens, including high, medium, and low, which can be determined according to the situation.

Projection screens are also divided into many specifications according to different uses. Yes, there are home, school, KTV and so on.

Tira curtain

Gain: The reflection characteristic (brightness of each angle) inherent to the curtain is represented by a number. A certain amount of light is projected onto a completely diffuse scattering surface (that is, a reflection surface with the same reflectance in the directions of 180 degrees from top to bottom and left and right), and the reflection brightness at this time is set to 1. Then under the same conditions, the same light is projected in the vertical direction of the screen, and the brightness of the center point and the points on the same arc is measured. The ratio of this brightness to the brightness of the completely diffuse scattering is called the screen gain.

Half gain: It is an important indicator for measuring screen brightness. The center of the screen is the brightest point of the screen when viewed in the vertical screen direction. When the viewer deviates from the middle axis of the screen, the gain when the screen brightness is reduced to half of the maximum brightness is half gain. In addition, the observation angle when the screen's gain is reduced to half is called the half-gain angle, and the half-gain angle is also an important index to measure the screen technology. The larger the half gain angle, the more content we can clearly see on the screen.

The effect of screen gain on the image: The screen presented by the screen without gain is relatively flat and faithful, but it is easily affected by the environment and external light. Gained screens bring bright, rich, colorful pictures with less impact from the environment and external light. But the screen gain has a special inverse relationship with the screen's viewing angle, that is, the higher the gain, the smaller the viewing angle. If the gain is too high (the half gain angle is too small), it will cause the middle of the picture to be bright, the effects of the four corners dark, and the high-brightness part will be saturated without layering. Because the energy is too concentrated, only one or two seats in the horizontal direction can see bright, Bright picture. Therefore, the projection screen should be properly selected according to different applications. The higher the screen, the better.

The aspect ratio of the projection screen directly affects the quality of the picture. Only when the aspect ratio of the projection screen and the natural resolution of the projector and the resolution (resolution) of the signal source completely match will the display screen be more exciting. The aspect ratio of the projection screen is mainly as follows:

1.33: 1 (4: 3), mainly video / PC images, diagonal x 0.8; width;

1.78: 1 (16: 9), mainly HDTV images;

1.85: 1, mainly for widescreen TV signal images;

2.35: 1, mainly used for wide-screen stereo image display.

At present, 4: 3, 16: 9 video images are most commonly used, and users can choose which ratio of screens to use according to the display ratio of their own machine.

Contrast is very important for the uniformity and resolution of the picture. It mainly refers to the ratio of high level and low level. In popular terms, it is the ratio of the bright and dark areas of the screen. A high-contrast screen is essential for the hierarchical display of the picture.

The uniformity of the screen is not only reflected in the quality of the picture, but also closely related to the projection technology of the projector. Good uniformity can ensure the consistency of screen brightness and color when the screen is viewed from 0 degrees to 180 degrees in the horizontal and vertical directions. The uniformity of the screen surface material complements the uniformity of the picture of the projector.

When selecting a projection screen, the above-mentioned parameters are usually considered in combination with the actual application requirements. The following points need special attention.

This is a seemingly simple and reasonable requirement, but there will be a lot of uneven "waves" on the screen in the application, which will deform when the image is projected on it. Moreover, the front and back of the screen are uneven, which also easily leads to the difference in the projection distance, and finally leads to inaccurate focusing, which affects the sharpness of the image.

Most screens look white, but in fact, different curtains have different reflection characteristics of light, and the reflectance of different colors of light is also different.

To compare two commonly used front projection screens:

Screen size is generally expressed in inches, such as 80 inches, 120 inches, and so on. Since the focus distance of the projector determines the distance between it and the screen, according to the distance between them and the height and width of the room where the screen is installed, you can calculate how large the screen should be installed.

The viewing distance is generally between three and five times the effective picture height. The viewing distance also has a certain adaptation period: when it is just used, the distance of five times the screen height feels more comfortable, and in the future, the distance of three times the screen height will feel more shocking.

Projection screen to fit installation conditions

The installation of the projector also requires the purchase of curtain materials. Due to the diffuse scattering screen (white plastic screen), it will reflect the incident projection light back in all directions, so whether the projector is hung or not has little effect on the picture quality. The recursive curtain (glass bead curtain) is different. It reflects directly where the light source comes from. Due to the narrow viewing angle of ordinary bead curtains, if the projector is hoisted, sitting at normal viewing height will feel that the picture is much darker than when standing at the height, and the picture quality is degraded.

Projection screen with installation height

The ideal screen installation height is such that the center position of the effective screen of the screen and the eyes of the viewer are at a slightly higher position on the same horizontal line. Many screen manufacturers often ignore this point. In order to reduce costs, the black part above the screen is made extremely short when the screen is produced. When the screen is installed, it encounters a high-level use environment on the floor. The picture is too high from the ground, and the user must look up at the picture at a large angle, which affects the viewing comfort, and the long-term look up also hinders the health of the viewer.