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  Device for camouflaging specularly reflecting surfacesUSPTO Application #: 20070222659Title: Device for camouflaging specularly reflecting surfaces Abstract: A camouflage device for camouflaging specularly reflecting surfaces of an object is formed with function elements for influencing the reflection of radiation from an assumed radiation source. Each function element forms a part of an outer layer and has a pair of individual surfaces on its side facing the radiation source. The individual surfaces extend longitudinally side-by-side, and their surfaces are arranged at an angle to one another. The camouflaging device is arrangeable on the object by means of a mechanism such that it is disposed in front of the reflecting surface; and the angular arrangement of the respectively assigned individual surfaces extends such that the surface normal of a first individual surface is sloped downward, and the surface normal of a second individual surface points more steeply than 80° to the horizontal plane, and their surface courses form an angle of <90° with respect to one another. (end of abstract)
Agent: Crowell & Moring LLP Intellectual Property Group - Washington, DC, US Inventors: Ralph Bofinger, Alexander Hoffmann USPTO Applicaton #: 20070222659 - Class: 342003000 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070222659. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The invention relates to a device for camouflaging specularly reflecting surfaces. BACKGROUND OF THE INVENTION [0002] In the field of long-range radar systems, so-called "phased-array antennas" are part of the state of the art. A special characteristic of these antennas is a plane exterior surface in the viewing direction of the antenna array. Because the viewing angle of this antenna arrangement is azimuthally considerably restricted but a 360.degree. view is required for an operative marine application, this antenna system is periodically rotated about its vertical axis. For an optimal detection of the elevation (total angle of the upper half-space=90.degree.), a basic alignment of the array surface in the range of 45.degree. with respect to the horizontal plane is required in this case. [0003] Based on this background, a problem is detected which occurs in the spectral range of between 0.4 .mu.m-5.0 .mu.m (VIS, NIR, SWIR and MWIR). The plane surface, which forms the outer end of the antenna in the transmitting and receiving direction and which, in the case of an implemented typical antenna, has a surface of 21n m2, represents a considerable reflector for the sun. It is another difficulty that, because of the basic alignment as well as the continuous rotation, the angular condition for specular reflections is met for a wide range of the solar altitude angle as well as of the observer's angle with respect to the sun. A flashing sun reflex of a signal duration of typically approximately 0.3-0.7 s can be observed, which is easily detected by an imaging sensor in the entire spectral range of the solar radiation (VIS, NIR, SWIR and MWIR) and can unfortunately also be classified because of the conceivable low piece numbers of the installed antennas. [0004] In this case, a specular degree of reflection of a few percent will be sufficient for increasing the reflected intensity far above the ambient brightness. For the purpose of a comparison: Depending on the amount of dirt and the orientation, an uncoated plane glass pane reflects 5 to 8% of the incident intensity and, depending on the size, supplies a conspicuous signal over a distance of 20 km for imaging sensors. [0005] The following applies to a typical antenna: Up to an observer's distance of 0.5 km, the width of the antenna fills the entire angular dimension of the sun; at a distance of 10 km still 5% or barely 1 mrad; that is, for most imaging sensors, more than one pixel width. A geometrical "dilution" occurs only at a multiple of this distance; that is, as a rule far behind the horizon. The decisive factor in this case is the large dimension of the almost perfectly plane face of the antenna. A reduction of the spectral degree of reflection (black color) for suppressing the specular reflex would have to be changed to far below 0.5%, which can virtually not be achieved according to the generally known state of the art. [0006] Wide-spread technology would suggest the use of a dull lusterless color. In this case, normally microscopic structures (area 10 .mu.mO) in the form of pigments or cavities are placed in the surface. However, this is always connected with a high susceptibility to contamination, particularly by means of drops of water. In the surroundings of a battleship, particularly in the proximity of the diesel exhaust gas system, this is very unfavorable; that is, it cannot be maintained for extended time periods because the surfaces have to be cleaned frequently (for example, twice a week), and in this case would lose their dull characteristic just as a result of material ablation. [0007] Furthermore, camouflaging elements are known from German Patent Documents DE 199 55 608 C2 and DE 197 10 692 C2. SUMMARY OF THE INVENTION [0008] It is an object of the invention to achieve a lasting effective suppression of the specular reflection by means of simple devices. [0009] This object is achieved by the camouflaging device according to the invention is provided for camouflaging specularly reflecting surfaces of an object, which has function elements for influencing the reflection of an assumed radiation source. Each function element, as part of an outer layer, has a pair of individual surfaces on its side facing the radiation source, which individual surfaces extend side-by-side in the longitudinal direction, with their surfaces arranged at an angle to one another. The camouflaging device can be arranged on the object by means of a mechanism such that, with respect to the assumed position of a radiation source, the camouflaging device is arranged in front of the reflecting surface and the angular arrangement of the respectively assigned individual surfaces extends such that the surface normal of a first individual surface 21 is sloped downward, and the surface normal of a second individual surface 22 points steeper than 80.degree. to the horizontal plane, and their surface courses form an angle of <90.degree. with respect to one another. [0010] In the case of the camouflaging device, the actual width of the individual surfaces may be between 2 and 5 mm. [0011] When the camouflaging device is used for camouflaging an antenna, the rearward side of the outer layer facing the antenna may have a pair of individual surfaces which extend side-by-side in their longitudinal direction and whose surfaces are arranged at an angle with respect to one another in order to at least partially compensate distortions of the antenna radiation because of the structuring of the outer side of the outer layer. [0012] Furthermore, a camouflaging device is suggested for camouflaging specularly reflecting surfaces of an object to be camouflaged having function elements for influencing the reflection of an assumed radiation source, each function element having, as part of an outer layer, on its side facing the radiation source, valleys and elevations with differences of height of between 2 and 4 mm, the width of the valleys being one to two times larger than the depth of the valleys, in which case the camouflaging device can be arranged on the object by means of a mechanism such that the longitudinal direction of the valleys and elevations extends in a horizontal plane while the fluctuation width is .+-.10.degree.. [0013] According to the invention, the problem is solved, not as in the prior art by the reduction of the degree of reflection, but by eliminating the specularity. [0014] For this purpose, the solution according to the invention provides a macroscopic breaking-open of the surface by structures in the range of .gtoreq.1 mm. [0015] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is a schematic representation of a ship having an antenna as well as a camouflaging device according to the invention arranged thereon, having function elements which, in a first embodiment, is additionally schematically shown in an enlarged representation; [0017] FIG. 2 is another view of an antenna with an alternative embodiment of the function elements. DETAILED DESCRIPTION OF THE INVENTION [0018] The camouflaging device according to the invention is used for camouflaging specularly reflecting surfaces. These surfaces may be components of, for example, an antenna, a radar absorber, a building wall or a wall of a vehicle, such as a ship or a land craft. As an example of a use of the invention, FIG. 1 shows an antenna on a ship, which has the camouflaging device according to the invention. [0019] According to one aspect of the camouflaging device 1 according to the invention, reflections, which occur because of the radiation of a radiation source and particularly of the sun on an outer layer 10 facing the radiation source, are compensated for an outside observer or a sensor. For this purpose, the outer layer 10 has function elements F which are arranged side-by-side in the longitudinal direction L. [0020] On its side facing the radiation source, each function element has a pair of individual surfaces 21, 22 which extend side-by-side in the longitudinal direction L and their surfaces extend at an angle with respect to one another. The angular arrangement of the respectively assigned individual surfaces 21, 22 is provided such that the surface normal 31 of a first individual surface 21 is sloped downward (i.e., it points below the horizon) and the surface normal 32 of a second individual surface 22 points steeper than 80.degree. to the horizontal plane. Furthermore, the arrangement of the individual surfaces 21, 22 of a function element of the outer layer 10 is arranged such that their surface courses form an angle of <90.degree. with respect to one another. As a result, it is ensured that the outer layer does not act like a retroreflector. Because of this design, the specular reflex becomes either larger than the altitude of the radiation source (for example, the solar altitude) or lower than the horizon for each position of the radiation source relative to the camouflaging device 1. By this measure, the area of a probable observer or sensor is left free barely above the horizon. However, this does not interfere with the main usage cases of invention. The viewing direction of an assumed observer or sensor close to the rays of a radiation source aimed at the camouflaging device empirically represents a situation of a relatively short duration which is difficult to evaluate. Continue reading... Full patent description for Device for camouflaging specularly reflecting surfaces Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Device for camouflaging specularly reflecting surfaces patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Device for camouflaging specularly reflecting surfaces or other areas of interest. ### Previous Patent Application: Selective reflective and absorptive surfaces and methods for resonantly coupling incident radiation Next Patent Application: Encoded transmitted signals in a simultaneous dual polarization weather system Industry Class: Communications: directive radio wave systems and devices (e.g., radar, radio navigation) ### FreshPatents.com Support Thank you for viewing the Device for camouflaging specularly reflecting surfaces patent info. IP-related news and info Results in 1.09522 seconds Other interesting Feshpatents.com categories: Daimler Chrysler , DirecTV , Exxonmobil Chemical Company , Goodyear , Intel , Kyocera Wireless , |
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