Due to the extreme dependence of our thermal emission characteristics on the thermal wavelength due to the extreme dependence of our thermal emission behavior on the wavelength, only certain wavelengths are suitable for thermal measurements. The following graphs show the range of thermal transmission for common window and thermal lenses for infrared thermometers. The blue-colored curve demonstrates the general rule applicable to all materials and shows the average value across the temperature range from zero (black) to infinity (green), which is known as the cold-pressure limit (CPL).
The cold-pressure limit, which is used for lenses and windows is the highest recorded value of a material’s damping rate against the thermal gradient. This ratio is calculated as a function the temperature difference across the angle of view for given viewing angle and cte of a window or lens. The bending moment of a system is the variation in the angle of incidence, which is linear or spherical. This results in the slope being proportional to the curve. The focal length of an entire system is also a factor in the slope. It is thought of as a function the focal length divided by the length of the curve (i.e. the time between shots).
For a particular set of temperatures and a specific focal length of a window or lens assembly, the inside surface temperature of the system will always fall within the prescribed curve in a perfect regularity called a “curved surface.” The thermal conductance curve of a glass bead within a glass vial can be plotted as a function the focal length and the temperature difference between the bottom and the vial’s surface and the angle of incidence of a particular window. If the aperture is fixed for all shots, then the area between the system’s surface temperature and the curve of variation will remain constant. If the aperture is variable, then the curve may be curved because of the variation in the temperature of the glass used in the making of 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 signature left by an artist on a flower is an example of a curly surface.
The process of mounting a lens and window should be done in a way that their focal points, and lines of sight are correct. If the internal temperature of the system is too cool for the lens, then the outside surface temperature of the frame will be lower and the inside of the lens will be too hot. If the outside temperature of the lens and the frame are equally and the frame is at the same temperature, it will not require any adjustment to counteract the effects of heating or cooling of internal temperature differences. The inside surface temperature of the frame will be in line for a particular focal length without the need for any other adjustments, as long as there is no external cause of temperature fluctuations affects the system. However, if the camera is installed in a location with an obstruction or limited view of any surrounding scenery or building and the surrounding area, then internal temperatures might need to be controlled.
The first mechanical interlocking systems that were used to attach lenses to cameras were made of plastic or other materials that would bend or mold according to changes in mounting pressure. This design was later adapted to pinhole glasses. This kind of lens assembly is not without a problem that the mechanical joints between the lens and frame might break or become indented. If this were to happen the result is necessary to replace the entire system in a relatively short amount of time. This is the reason why this system has been replaced with more durable models.
Lenses that are designed to be used with pinhole glasses typically come with a metallic frame and a thin glass or plastic lid. At a minimum the lense designs must include a hermetically sealed lens construction. A hermetically sealed lens construction has a sealed surface on the top and bottom of the lens assembly. The top surface could contain an electronic seal similar to that previously mentioned. It could also contain another substance, such as an adhesive, lip, or a layer of plastic film.
A lens surface that is a substrate and adheres to the base is another example of this type of window and lens assembly. The system typically consists of a glass casing and a series of lens compartments. Other kinds of devices can be used in the windows, for example, light emitters and thermometers. In some cases, the device used to control the temperature of the room might also be part of this type of system. In this scenario, a series of compartments could be used to house the temperature controller together with a variety of other devices, like an alarm clock or thermostat.
This isn’t an exhaustive list of all types of lens and window assemblies. However, it is indicative of the most important technologies that are associated with this invention. Please refer to the complete disclosure for more details. In particular, you should read the portions relating to “details of the present invention” and “Description of the Process With Regard to the Identification of the Different Classes of Products That Are Included in the Present Applica.”
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