+8618117273997 weixin
en English
Posttime: 29 Feb, 2012 Views: 94 Author: Jacky

LED Light Output Efficiency 5 Conclusions

Seen from the relatively light intensity distribution curve of LED chip, the radiation of the platform irradiance p-n junction belongs to Lambertian type, namely the beam intensity changes with the cosine of the emergence angle. It is reasonable to simplify p-n junction to point light. It is reliable to calculate the light intensity by using Fresnel transmissivity formula, the chip relatively light intensity distribution curve and this kind of light intensity calculation method will be the basis of studying the complicated packaging structure.

Seen from figure 6, when neglecting the light absorption of the packaging materials, the output efficiency of LED with hemispherical packaging will amplify with the growth of the refractive index of the packaging materials. However, the refractive index of the present epoxy resin packaging materials is always in 1.4-1.6, the change is limited; therefore, we should look for the new packaging materials through other methods to improve the light output efficiency of LED.

The cylinder height has a certain influence on LED efficiency, the higher the cylinder is, the side area is larger, the light loss is more, which will cause the decline o the overall efficiency. Usually, in order to decrease the light loss of the side face, we put a reflection cup behind the chip; therefore, the influence of the cylinder height is relatively small, which is our next study subject.

About Lisun Group:

Lead in CFL and LED Tester. Click to our product lists:

Goniophotometer
Spectroradiometer
Integrating Sphere
Colorimeter and Photometer
LED Test Instruments
CFL Testing Instruments
EMC testing
Electronic Ballast Tester
Equipments for Testing Electronic components
Electrical Safety Tester
Environmental Chamber
AC and DC power supply
Spectrophotometer

Tags:

Leave Message

Your email address will not be published. Required fields are marked *

=