(US4850660-A)      Article comprises a substrate which includes restrahlen peaks of reflectance at 10 and 22 micron regions and includes a high emissivity coating. Coating comprises a stack of multiple thin alternate layers of 2 or more materials. One layer comprises a material normally having a high internal stress so as to preclude or render undesirable a normal quarter wave thickness layer deposition and index of refraction close to the substrates. Other layer includes an absorber material with complex index of refraction which is a function of wavelength and close to the substrates, such that stack thickness is quarter-wavelength(s) total w.r.t. infrared region of the spectrum.    USE/ADVANTAGE -   Active in the visible and infrared wavebands of the spectrum in man-made satellites.    (8pp)    (GB2193819-B)      An article for use over a spectrum including the visible wavebands and the infra-red wavebands of between 6 and 30 microns, wherein the article comprises a substrate of the type including restrahlen peaks of reflectance at about 10 to 22 microns respectively and a coating giving the article greater emissivity than the substrate alone, and wherein the coating comprises a stack of multiple alternate optical layerss of at least two materials, one of the materials being a material normally having a high internal stress which would preclude or render undesirable normal quarter wave thickness deposition, and an index of refraction relatively close to that of the substrate, the other of the materials being a material which acts as an absorber with a complex index of refraction which is a function of wavelength and is also relatively close to the index of refraction of the substrate, the optical thickness of the stack amounting in total to a quarter-wavelength or multiples of a quarter-wavelength in the infra-red region of the spectrum.    (JP2694951-B2)      An element, for use over a spectral range including the visible and 6-30 microns IR wavebands, has a high emissivity coating on a substrate of the type exhibiting residual radiation reflection peaks in the 10-22 microns region.    The novelty is that the coating comprises a sequence of thin alternate layers of two material. One of the materials normally has a high internal stress and a refractive index close to that of the substrate. The other material acts as an absorber with a complex refractive index, which is a function of the wavelength and which is opt. close to the refractive index of the substrate. The total optical thickness of the sequence amounts to (a multiple of) a quarter wavelength in the IR region of the spectrum.    USE/ADVANTAGE -   The element is useful as a cover slip for the solar cells e.g. of artifical space satellites or as a heat control mirror for satellites it has improved emissivity and allows use of extremely thin layers without problems of cracking caused by internal stresses.    (DE3725871-C2)      An element, for use over a spectral range including the visible and 6-30 microns IR wavebands, has a high emissivity coating on a substrate of the type exhibiting residual radiation reflection peaks in the 10-22 microns region.    The novelty is that the coating comprises a sequence of thin alternate layers of two material. One of the materials normally has a high internal stress and a refractive index close to that of the substrate. The other material acts as an absorber with a complex refractive index, which is a function of the wavelength and which is opt. close to the refractive index of the substrate. The total optical thickness of the sequence amounts to (a multiple of) a quarter wavelength in the IR region of the spectrum.    USE/ADVANTAGE -   The element is useful as a cover slip for the solar cells e.g. of artifical space satellites or as a heat control mirror for satellites it has improved emissivity and allows use of extremely thin layers without problems of cracking caused by internal stresses.