Patent ID: 7576932
Filing Date: 2009-08-18
Classification: G02B,G03B,H04N

Abstract:
1. A prism assembly comprising two or more prisms, at least one of which comprises one or more surfaces that are used for total internal reflection or partial spectral reflection of incoming light, wherein at least one of said surfaces used for reflection purposes is spaced apart from another prism such that a first air gap is formed between said prisms, said prism assembly further having an element that is spaced apart from said surface used for reflection purposes, such that a second air gap is defined in between said surface used for reflection purposes and said element, and such that said second air gap is adjacent to said first air gap such that the first and second air gaps share a common edge, said prism assembly further having a seal that seals an air gap formed by the combination of the first and second air gaps in order to prevent contaminants from entering said air gap and such that total internal reflection or partial spectral reflection of incoming light is not influenced by the presence of said seal.