Patent ID: 6297918
Filing Date: 2001-10-02
Classification: G02F

Abstract:
A passive optical limiter for protecting a light-sensitive object from damage due to an incident light beam above a first predetermined value of light intensity, said passive optical limiter comprising:first optical means for focusing an incident light beam to a focal point;a protective element disposed near the focal point, said protective element being responsive to a focused incident light beam below the first predetermined intensity level for passing therethrough the focused incident light beam below the first predetermined intensity level, said protective element being responsive to a focused incident light beam between the first predetermined intensity level and a higher second predetermined intensity level for deflecting by way of thermal defocusing substantially all of the focused incident light beam into rings of light and passing therethrough only a small portion of the converged incident light beam between the first and second predetermined intensity levels, and said protective element including means responsive to incident light at or above the second predetermined intensity level for scattering that incident light in all directions to decrease the intensity level of the incident light below a damage threshold of the light sensitive object; andsecond optical means for focusing substantially all of the light passing through said protective element and said second optical means onto the light-sensitive object.