How to select standard sight source and tested samp

1. The allowable tolerance range of standard light source calibration and retest results is as follows:

X, Y Chromaticity Coordinates: ±0.0008
Color Temperature: ±10K
Luminous Flux: ±5‰

2. The allowable tolerance range of contrast light source/ luminaires retest results as follows:

X, Y Chromaticity Coordinates: ±0.0050
High Color Temperature: ±150K
Low Color Temperature: ±100K
Luminous Flux: ±3%
Description: The contrast light source means to checking whether the tested light source have some data tolerance which caused by current environmental or not. After retesting the tested light source, we comparing the both test results and see whether the current test result have tolerance or not. By application contrast light source, it is can quick and high effective to do tolerance confirmation, it also can reduce the contrast light source’s using chance to improve the life time.3. The main parameters for judging the light source and luminaries:
1) Color Rendering Index (CRI):
For LED bulbs, which compared with Incandescent Ra=100, CFL Ra=80:
Ra≥75 is the better CRI.

When Ra is between 62~65 is the common case.

2) Power Factor (PF) (the Energy Star requirement):

<5W, no requirements

>5W, requires PF>0.7

3) Power:

Nominal value ±10%

4) Luminous Flux:

LED lamp bead meets the requirements of 100~120lm/W is better.

5) Luminous Efficiency

<55lm/w: Poor
55~70 lm/w: Common

>70 lm/w: Good


LED Modules: Color Difference should meet ≤7SDCM

4. About the calibration of light source and the measured lamp (SSL products), the US Energy Star IESNA-LM-79 standards specifically stated in section 9.1.2. The specific requirements are as follows:

1) Standard lamps for total spectral radiant flux are normally quartz-halogen incandescent lamps that have broadband spectrum to calibrate the spectroradiometer for the entire visible region. For the 2πgeometry, standard lamps having only forward distributions are required. For example, a quartz-halogen lamp with a reflector providing appropriate intensity distributions may be used as a reference standard source. For the 4π geometry, standard lamps having omni-directional intensity distributions are commonly used but standard lamps having forward intensity distributions may also be needed. Note that the light output of incandescent standard lamps changes if their burning position is changed.

2) It should be noted that integrating spheres do not have perfectly uniform responsivity over their internal sphere surfaces. The sphere responsivity tends to be slightly lower for the lower half of the sphere due to contamination by falling dust, and also around the sphere seams where small gaps exist. Therefore, if a sphere (4p geometry) is calibrated with an omnidirectional standard lamp and measures an SSL product having downward intensity distributions, the luminous flux tends to be measured slightly lower than it is. This error tends to be more prominent for light sources having narrow beam distributions. The magnitude of errors depends on how well the sphere is designed and maintained, and will be cancelled if the angular intensity distributions of the standard lamp and the test SSL products are the same.

3) To ensure that this error is not significant, standard lamps having different intensity distributions (omnidirection, downward/broad, downward/narrow) may be prepared and chosen for the type of SSL products to be measured. Or, if only omni-directional standard lamps are used, correction factors should be established and applied when SSL products having different intensity distributions are measured. Such correction factors may be established by measuring lamps or SSL products having different intensity distributions calibrated for total luminous flux using other accurate means (e.g., calibration traceable to national measurement institute (NMI), or using well-designed goniophotometer).