Preface

This paper focused on the use of PMMA or PC material for high power LED lens (entire reflection cup) working principle.

Explain.

1. For entire reflection cup LED lens, the optical path principle is as shown below;

2. lens structure is including of two parts:

2.1 directly in front of the LED light is transmitted through the inside a small surface of LED lens ( A )by penetrate the ways to gather light, just like the above pictured in blue light;

2.2, beyond the small surface (A) diameter outer side light through the lens of the reflecting surface (B) to gather light by the reflective ways in the green light;

3 how does lens (A) and (B ) blue light green light in the two part of the light projected formed by the spot should be overlapped into a spot, it is the focus of the design;

4 when (A) penetrates the surface displacement, this part (blue) light condenser angle becomes smaller, then the LED in front of a part of the light will be beyond the surface (A) to (B) further reflection, then if the reflecting surface (surface area) is unchanged, a part of the light to and from beyond the reflector outside run project, this part of the light is more than popular stray light or light (such as the red part)

5 ( A ) penetrates the surface coefficient and distance of LED will be change, then in front of the concentration, it is also change in angle; ( B ) reflecting surface coefficient and diameter ( area ) willInfluence light condenser angle of the LED ，also ,it will influence the utilization ratio of light; so that ( A ) and ( B ) is the through the computer to complete the design testing.

6 when the reflecting surface is enlarged in diameter, equivalent to a reflection surface area increases, although it can enhance the lens reflection efficiency, but the LED lens volume also increases accordingly, to large volume, the bad effects is below: materials, injection time and shrinkage rate increases, it is rising costs even increasing the thickness of optical loss increase center, etc.;

7 entire reflection cup lens (clear surface) is suitable for the condenser design below 45 degrees. in order to obtain different effects (such as: diffuse facula, rectangular facula, oval facula and so on),you can changes in lens surface（such as cambered surface, frosting surface, ledns array, fresnel surface and so on）