OpticalManufacturers

http://www.alibaba.com/product-gs/207984016/Optical_Lens.html

http://www.alibaba.com/product-gs/213697809/plastic_lens.html Used in PIR systems

lens manufacturers
LED optical lenses to focus the beam.

collimator lens /?? what is collimator

http://www.directindustry.com/prod/jenoptik-polymer-systems/fresnel-lens-17956-148994.html

http://www.alibaba.com/catalogs/190404/Lenses.html

plastic lens:1.used for PIR sensor and alarm 2.we can make different kinds of lens for you!...

http://www.alibaba.com/product-gs/213697809/plastic_lens.html