Definition: It is the hollow spheres used for the photometry. The inner surface of the sphere is coated with the selective ( even ) defuse reflection whitewash. The illumination of any directions of the sphere is equal.
Characteristics: It is the hollow sphere with high reflective inner surface. It is a high-efficient device used for collecting the scattering or emission of light for the test sample in the position of the sphere inside or outside and near the window. The small window in the sphere can let the light enter and be close to the detector. The integrating sphere is also called the optical ball; it is the hollow complete spherical shell.
The inwall is coated with the white diffuse layer, and every point on the inwall evenly diffuses. The illuminance produced by the light source on any point of the ball is overlapped by the illuminance produced by the reflecting the light for many times.
Coating of the integrating sphere: The coating reflectivity on the inwall of the sphere and the transmissivity of the integrating sphere are the most quality index of the integrating sphere.