The LED total luminous flux measurement has absolute and relative measurement two methods. Relative measurement’s method is more simple than absolute measurement’s method, less investment in equipment .
Be used for luminous flux’s relative measurement of integrating sphere is a complete hollow spherical shell, The sphere’s in wall evenly sprayed white diffuse layer,Open a window over the sphere’s in wall, placed the metering light source on the sphere,The light source send out lights go through after in wall’s reflex ,shine out on the window’s detector,The detector received signal are proportional to the luminous flux of light source.
Use the integrating spheres measuring the method of the total luminous flux. Do the following assumptions:
1)Integrating sphere in wall is an uniform ideal diffuse layer , comply with the Lambert’s law;
2)The diffuse coefficient of each point in the integrating sphere is equal;
3)Integrating sphere in wall’s white pigment for light source send out various wavelength ray of light with the same diffusion coefficient,namely sphere in wall’s diffuse is neutral;
4)The diameter of the sphere is the same everywhere,except the light bulb in the sphere in wall, no other stuff.