GB/T 32200-2015Characteristic parameter and measurement of projection screens (English PDF)

2.1 Projection screens

For screening with a predetermined light reflection and transmission optical properties of the screen surface.

2.2 D-type screen typeDscreen

Also known as diffuse screen. D-type screen incident light diffusely reflected in the 2pi solid angle space, the brightness coefficient Polar curve

Close to ideal diffuse semicircle.

2.3 B-type screen typeBscreen

Known as the reflective screen gain on the angle of incidence. B-type screen of the incident light is reflected in the solid angle 2pi space having the angle of incidence of light

Agglomeration gain reflection characteristics.

2.4 S-type screen typeSscreen

Also known as the angle of reflection on the gain reflecting screen. S-type screen of the incident light is reflected in the 2pi solid angle of the light reflection angle having a space

Agglomeration gain reflection characteristics, size or angle of reflection equal to the angle of incidence.

2.5 R-type screen typeRscreen

Also known as transmissive screen. R is a transmission type screen to watch the screen light, transmitted light gathering gain direction coincides with the direction of the incident light.

2.6 Luminance factor

When given the same lighting conditions and viewing angle, the brightness of the reflection brightness of reflected or transmitted over the surface of the measured diffuse screen than

Values, such as the formula (1) below.

beta =

Ly

L1 (1)

Where.

beta --- brightness coefficient;

Ly --- given viewing angle of the screen brightness of reflected or transmitted, in units of candela per square meter (cd/m2);

L1 --- given viewing angle on the reflective brightness over diffuse surface, in units of candela per square meter (cd/m2).

In practice, in order to diffuse reflection plate instead of over standard diffuse surface, due to the brightness of the diffuse reflection coefficient is less than the standard plate 1, the formula (1)

Become a formula (2).