Principle of Operation:  Reflective film stretched across a rigid 4’ diameter ring.  Integral hand pump/handle
assembly creates a vacuum inside the ring, causing the reflective film to form into a smooth concave mirror that
focuses light into a 4-6” spot.

Mirror Diameter-                        45”
Reflective Surface                     Aluminized Polymer Film
Reflective Area                         11.5 Sq. Ft.
Weight                                       8-10 lbs., depending on configuration

Point Focus
Minimum Focal Length             8 Ft.
Minimum Focal Area                4”
Concentration                          130 suns
Time to Boil 48 Oz. of Water    7 minutes (at 900 w/msq. sunlight intensity)
Vacuum Hold Time                    2-3 days- always cover dish when not in use
Maximum Heat Flux                   1300 F   
Test Data
Degrees F
Test Procedure:
Focal point directed onto a 4" dia. copper
plate, with a Type K thermocouple attached.  
Back of copper plate was insulated.
A Better Focus Co.
Product Specifications
sunlight intensity
U.S Patent # 7,374,301