Very thin multispectral filters for high spatial resolution observation satellites

Paper number

IAC-09.B1.I.2

Author

Mr. Roland LE GOFF, EADS Sodern, France

Coauthor

Mr. Gilles Corlay, EADS Sodern, France

Coauthor

Mr. Yves Kocher, EADS Sodern, France

Coauthor

Mrs. Karine GASC, Centre National d'Etudes Spatiales (CNES), France

Year

2009

Abstract

Thin multi-spectral filters providing spectral filtering and spatial separation for each spectral band, assembled onto the corresponding multi-linear CCDs, allow the acquisition of terrestrial images with a “spectral content”. The filter technology, which employs optical-based lithography lift-off processes and known as “patterned filter”, is well suited for a variety of applications. It is in particular already used in space borne instruments such as those of the Pleiades and CBERS satellites.  In both cases SODERN detection modules are used. 

The Pleiades patterned filter corresponds to the current state of the art technology. However current developments of new generation of sensors have already generated the need for a greater number of bands and for higher absolute radiometric accuracy, which leads to possible concerns like cosmetics aspect and straylight, with a particular attention to ghost images and crosstalk between spectral bands.

A possible technology to fulfill these new requirements is to assemble elementary strip filters into so called “assembled filters”. This alternative design is also expected to be more cost effective and to provide more flexibility during manufacturing processes. Assembled filters are under development at SODERN and prototype results have already proven their capabilities: size as long as about 80 mm, ten separate spectral bands and typical spacing between bands of 1 mm.

This paper recalls the current state of the art of the patterned filters, with the example of the French Pleiades program, and then describes in details the design, characteristics and advantages of the assembled filter technology.

Abstract document

IAC-09.B1.I.2.pdf

Manuscript document

IAC-09.B1.I.2.pdf (🔒 authorized access only).

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