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We all know that DLP uses a large number of optical components, and dust is quite harmful to optical components, so the protection of large screen for dust is very key. Dust may have many effects on it, which are shown in the following four points:

1. Color wheel damage

The rotation speed of the color wheel is quite high, about 7200 revolutions per minute. When the dust protection is not good, the dust accumulation will gradually adhere to the wheel, resulting in the unbalanced rotation of the DLP wheel, just like the general principle of body vibration caused by the unbalanced wheel of the car. The color wheel will vibrate and damage the motor. In addition, it may also reduce or stabilize the speed of the color wheel, resulting in failure.

2. Brightness decrease

In case of serious dust falling in the environment, the brightness of DLP may be reduced by more than 40% within half a year. Generally, the reflectivity specification of the new reflector is more than 98% and the transmission law specification of the lens is more than 97%. These requirements are very high in order to obtain high-efficiency output brightness. When the dust protection is not good, the dust accumulates on the surface of optical components, The reflectivity and transmittance decrease with time, resulting in the decrease of brightness.

3. Contrast decline

The definition of contrast is that the maximum brightness value that can be output by the DLP display unit is divided by the darkest brightness value. When in a dark scene, the dust on the DLP optical components will reflect stray light and project the light that should not be projected from the lens to increase the brightness of the dark part. Similarly, in the bright part, part of the light will be blocked by dust, reducing the reflection and transmission of light, and reducing the brightness value of the bright part. This contrast naturally decreases.

4. The sharpness decreases and the image becomes blurred

The reason for the decrease of clarity is the change of refractive index of DLP optical components. When the lens or the surface area of the lens is dusty, it is like a layer of bad material with irregular refractive index on the surface of the lens, resulting in the change of the path of light and the focus is not on the same focus, making the imaging blurred.