Just as US said, Laser TV need a professional anti-light screen:
So which kind projection screen is the best option? There a two kinds: Black Grid Screen or a Fresnel Screen, which one is the best one? Now let’s discuss the details.
First of all, although the two kinds of screens have different structures, they can be used with ultra-short focus projectors, and both rely on special optical structures to achieve directional reflection and anti-light. Today I will talk about the principles of the two structures.
Principles of the two Structures Laser TV Screen
First of all, the black grid structure, the principle is to use special technology to make the cross-section of the zigzag screen. As shown in the picture:
The black grid screen uses black and white prisms to absorb interference light while reflecting projection light. The white slant is a reflecting layer. The light from the projector is projected from bottom to top on the white reflecting layer and then reflected into our eyes. The interference light from above will be absorbed by the black parallel layer.
Here’s the Fresnel structure. To help you understand, let’s first give you an example of flashlight luminescence: the light bulb uses the convergence of the concave reflector in the front of the flashlight to gather the light, so that the light beam can be bright and straight. This principle is believed to be understood by many people.
The Fresnel structure actually uses the convergence principle of the concave mirror. It divides the concave mirror into a circle of circular structure and puts it on a plane. This can save a lot of useless space and explain it more abstractly. We have found some pictures on the Internet to help you understand.
In this way, the concave surface becomes a plane structure, but its function is the same as the concave mirror, because the screen can not be made into a large concave mirror, so there is the screen of Fresnel technology.
Fresnel anti-light curtain structure, the screen surface is full of semi-circular lines from large to small, this semi-circular structure is only sensitive to the projection light below the center of the circle, that is, it only reflects the light projected from the projector position, so if the Fresnel screen wants to achieve the desired effect, in order to design the structure, we must make the center point of the circle aligned with the lens of the projector as far as possible, so that the anti-reflection can be achieved. The light emitted is focused within a certain range, thus enhancing the brightness of the picture.
Contrast of Projection Effect
Different structures will naturally bring different effects, and even a phenomenon appears: “Fresnel” and “Black Grid” have their own “advocates”. What are the projection differences between them?
Brightness of Screen
Generally, the gain of screen with black-grid structure is 0.4-0.5. Some brands carry out coating processing on the basis of the original black-grid screen, which not only corrects the color temperature of the original coating, but also makes the screen gain reach 0.8, like Focusview.
Fresnel’s unique semi-circle structure can effectively focus the reflected light, thus enhancing the brightness of the picture, making the gain of the best angle of view increase to 1.0, and the positive brightness effect is excellent.
Compared with the positive brightness, the brightness of the black grid screen is inferior to that of Fresnel. Many people who like Fresnel screen pursue its high brightness.
The structure of black grid screen is a parallel prism structure.
Black Grid Screen
No matter where you sit, the brightness of the screen is the same, which greatly increases the viewing area.
Fresnel’s semi-circular structure, because the concave mirror principle, can let the brightness focus in a certain range, that is, the front position of the screen. (Imagine the Flashlight beam.)
Once deviated from the middle position, the brightness will be seriously attenuated and the viewing angle will be narrow.
Screen structure and reflection
The sawtooth structure of the black grid screen is located on the surface of the screen. This way can achieve better imaging and anti-light. The overall picture effect is clean and no reflection. The existence of the sawtooth structure can be felt by touching the screen surface gently with hands. But the disadvantage is that the curtain can not be scratched, once damaged can not be repaired, so installation and use need to be carefully maintained.
The Fresnel structure is located behind the resin layer on the screen, which can effectively protect the structure from damage and is closer to the surface appearance of LCD TV. This is an additional item on the surface.
Most of the projected light passes through the transparent resin layer, enters the structure and is reflected back. However, some of the light is directly reflected to the top of the screen by the transparent resin surface, forming a shadow on the top of the room.
The screen of Fresnel structure is hard screen, because the special optical structure can not be made into soft screen. While the black grid structure is both soft screen and hard screen, it meets the needs of different consumers.
At present, the maximum size of the Fresnel structure can only be 100 inches, while the maximum size of the conventional black grid can be 120 inches.
Notes: The screen for Laser TV or ultra short throw projector, can not be used for common home projector.
Now we know the difference of black grid screen and fresnel screen. So, what is your selection?
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