1. Field of the Invention
The present invention is directed to thermal imaging cameras and, more particularly, thermal imaging cameras suitable for use by a user who is crawling.
2. Background of the Invention
Thermal imaging cameras (TICs) are specialized cameras for use, for example, by firefighters, search and rescue workers, emergency workers, and the like, to view areas where there is heavy smoke, darkness or other areas where visibility is limited. A TIC is used, for example, to locate a seat of a fire, locate hot spots and size of an actual fire, find doorways and windows, locate trapped victims, etc.
The appearance and operation of TICs for firefighters and the like may be similar to a camcorder. Instead of CCD sensors which are commonly used in camcorders, most thermal imaging cameras use microbolometer arrays. The resolution of a TIC may be considerably lower than that of optical cameras. For example, the resolution of a TIC may be 160×120 or 320×240 pixels. Older bolometers required cryogenic cooling, usually requiring a miniature Stirling cycle refrigerator or liquid nitrogen.
Bolometers of the type for use with TICs for firefighters and the like typically use a grid of vanadium oxide or amorphous silicon heat sensors on a corresponding grid of silicon. Infrared radiation picked up by the TIC's lens hits the vanadium oxide grid and changes its electrical resistance. The TIC takes this resistance change and processes it into temperatures which are shown on the TIC's viewfinder. Bolometer grids are typically found in two array sizes: 320 by 240 or 160 by 120. Both sizes offer the same resolution. The 320 by 240 is capable of showing a larger field of view.
Bolometer technology of this type was originally developed in the 1980's in a classified contract for the U.S. Department of Defense. The US government de-classified the technology in 1992. After 1992, the technology spread to various manufacturers.
Numerous patents in the prior art teach the many different elements of TICs. For example, U.S. Pat. No. 6,649,912 (Salapow, et al.) is directed to a TIC having a seamless housing encompassing a TIC core. The TIC itself has bumpers at its edges but they do not extend out from the base of its handle to the same distance as that of those on the body of the TIC. The handle is not separable from the TIC itself. At column 7, the specification states that resilient bumpers cover all of the extremities or projecting portions of the camera such that if the camera is dropped at a flat surface, one of the resilient bumpers will always first contact the surface regardless of the orientation of the camera.
U.S. Pat. No. 6,787,775 (Bielefeld, et al.) is directed to a portable thermal imager with a shock-absorbing lens mount. The mount minimizes the transfer of impact forces to the lens. Although apparently not specifically discussed, the housing of this TIC does appear to have bumpers (as seen in FIG. 2). However, unpadded handles extend from the sides of this TIC further out than the bumpers.
U.S. Design Pat. No. 424,081 (Gordon) is directed to a hand held thermal imaging apparatus. Here, handles appear to extend from the housing of this TIC that are unpadded.
U.S. Design Pat. No. 472,911 (Bielefeld) is a design patent that is directed to a handle for the design of the '775 patent. While it is not clear, this handle appears to be a removable addition. Again, here, the butt end of the handle extends outwardly to form a base but this base does not extend as far out as the sides of the upper end of the handle adjacent to the TIC. Additionally, the side handles on the TIC here extend farther out than the upper end of the removable handle such that crawling with this camera is not suggested.
U.S. Design Pat. No. 479,548 (Bielefeld) is a design patent that is directed to what appears to be the same invention as that of the '775 patent, discussed above. Here, it can be seen that the handles extend out from the body of the TIC farther out than the bumpers as shown, for example, in FIG. 2.
U.S. Design Pat. No. 481,053 (Colburn, et al.) is a design patent directed to a TIC having a handle that is integral to the TIC. The base of the handle is of the same width as the top of the handle.
All references cited herein are incorporated herein by reference in their entireties.