Watching movies and TV on mobile phones likes to be directly projected on TV, so it's not tiring to watch. Then there are actually many ways to project a screen on TV, whether it is a TV set-top box, a converter or the screen projection function that comes with a mobile phone.
Screen projection is a basic network function provided by Android system, which supports real-time projection of mobile phone screen to any other large-screen device compatible with Miracast protocol. Miracast: supports real-time projection of all operating interfaces of mobile phones to other large-screen smart devices, which is no longer limited to streaming media.
Therefore, in addition to watching videos and pictures on the big screen, it can also be used for the operation demonstration of mobile phones and playing games on big screen devices.
Extended data:
Projection screen can be divided into hard screen and soft screen in material and manufacturing process.
The types and technical parameters of projection screens are interrelated, complementary and different.
The key to explore its technology is how the materials on the screen surface scatter, reflect and refract the incident light.
For the above two kinds of screens, there are two kinds of projection screen technologies on the market-soft screen and hard screen technology.
No matter what application mode, the main technology of front projection soft screen is to perform various operations on an opaque cloth surface.
Different materials were sprayed, but different optical materials were used for the surface materials. The number and distribution of optical factors in optical materials determine the gain, viewing angle and resolution of the screen.
At the same time, these optical factors and other pigments can optimize the color saturation and picture of the projected picture.
The projection light of the rear projection illuminates the screen from the back to form an image. The material of the soft screen is PVC .. The quality of the screen is also related to the surface material and screen material.
The manufacturing of hard screen mainly adopts optical diffuse reflection and Fresnel lens technology.
Diffuse reflection screen has the characteristics of large viewing angle, low gain, strong adaptability to ambient light and wide application range.
One of diffuse reflection screen technologies is to directly treat acrylic surface made of plexiglass. The viewing angle and clarity of the screen are not ideal, and the daylight effect is also serious.
Another diffuse reflection screen technology is made of transparent body materials, such as acrylic and glass. As a substrate, a rear projection soft screen is pasted on its surface.
The up, down, left and right viewing angles of the screen are all 180 degrees, which will not be affected by sunlight, and the size of this screen is generally relatively large.
Fresnel optical lens screen can increase the screen gain, but its vertical viewing angle is limited.
Fresnel optical lens screens are different according to the different pitch angles of Fresnel lenses, and the focal length of each screen is also different to meet the needs of projectors with different lenses.
References:
Baidu encyclopedia-projection screen