Due to the dependence of our thermal emission characteristics on the wavelength of the thermal due to the dependence of our thermal emission behavior on the wavelength, only a few wavelength ranges are suitable for measurements of thermal. The following graphs show the thermal transmission ranges of common thermal lenses and window materials for infrared thermometers. The blue-colored curve demonstrates the general rule applicable to all materials, and represents the average value over a temperature interval of zero (black) to infinity (green) which is the cold-pressure limit (CPL).
For windows and lenses, the cold-pressure limit is defined as the maximum measured value of the damping ratio of a substance against the thermal gradient. This ratio is calculated as a function of the temperature difference along the angle of view for given viewing angles and cte of a window or lens. The slope of this curve is proportional to the bending force of an entire system, which is the result when the angle of incidence shifts from linear to spherical. The slope of this curve is also proportional to the focal length of the system, which can be considered as an expression of the focal length divided by the length of the curve (i.e., the time between shots).
For a set of temperature and a given focal length of a lens or window assembly, the inside temperature of the system will always be within the prescribed curve in the perfect order known as a “curved surface.” For instance the curve of thermal conductance of a glass piece inside a glass vial having a hole in it can be plotted in relation to the focal length, the temperature difference inside the vial between the bottom of the bead and the surface of the vial, and the angle of incidence for a specific window assembly. If the aperture is fixed for all shots, then the area between the surface temperature of the system and the curve of variation for the particular window assembly must remain constant. If the aperture is variable this means that the curve could be curved as a result of the variation in the temperature of the glass used to create the bead, the temperature of the ambient atmospheric air on the inside surface of the vial, and the focal length and duration of shooting. A good example of a curly surface can be seen in the signature left by a photographer of the flower.
Mounting a lens and window should be done so that their focal points, and lines of sight, are in the correct direction. If the inside surface temperature of the system is too cold for the lens, then the outside surface temperature of the frame will be cooler and the interior temperature of the lens will be too hot. The frame won’t need to be adjusted to account for internal temperature variations or cooling effects. If there aren’t any temperature differences from outside, the system’s inside surface temperature will be the same for the given focal length. If the system is situated in an area that has limited or obstructed views of surrounding structures or landscape it might be necessary to control the internal temperature.
The first mechanical interlocking systems used to mount lenses to cameras were made of plastic or other materials that could change shape or bend depending on changes in mounting pressure. This design was later adapted for use with pinhole glasses. This kind of lens assembly is not without a problem: the mechanical joints between the lens and frame might break or be indented. If this were to happen then it is required to replace the entire system in a relatively short amount of time. Because of this the type of system has been replaced with more robust designs.
Pinhole glasses lenses are usually constructed using a frame of metal and a thin, plastic or glass lid. At the very least, these lense designs should have a hermetically sealed lens construction. A hermetically sealed lens has a sealed surface at the bottom and the top. The top layer could have a similar mechanical seal similar to that mentioned above. It could also include an adhesive, lip, or layer of plastic film.
A lens surface that contains a substrate and adheres to the base is an additional illustration of this kind of window and lens assembly. This type of system typically consists of a window casing as well as several lens compartments. The windows may also contain other kinds of devices, like light emitters or thermometers. In certain instances, the device used to regulate the temperature within the room could be part of this type of system. A series of compartments could be used to house the temperature control as well as a variety of other devices, such as an alarm clock, thermostat, or other devices.
This is not an exhaustive list of all types of lens and window assemblies. It’s an indication of the significant technologies that are connected to this invention. For more information, please read the entire disclosure. In particular, please read the portions relating to “details of the present invention” and “Description of the Method with Respect to the Identification of the Various classes of products involved in the Present Application.”
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