Because of the dependence of our thermal emission characteristics on the thermal wavelength, only a few wavelength ranges are suitable for measurements of thermal. The following graphs show the range of thermal transmission of standard thermal lenses and window materials for infrared thermometers. The blue-colored curve illustrates the general rule applicable to all materials, and represents the average value for a temperature interval of zero (black) to infinity (green) which is the cold-pressure limit (CPL).
The cold-pressure limit, which is used for lenses and windows, is the maximum measured value of a material’s damping coefficient against the thermal gradient. This ratio is plotted as a function of the temperature differential in relation to the angle of view for a specific viewing angle and cte of the lens or window. The bending moment of a system is the variation in angle of incidence from spherical or linear. This causes the slope to be proportional to this curve. The slope of this curve is also proportional to the focal length of a system, which is thought of as an expression of the focal length divided by the duration of the curve (i.e. the period between shots).
For a given temperature range and a specific focal length of a lens or window assembly, the inside surface temperature of the system will always be within the prescribed curve , in a perfect regularity called a “curved surface.” For instance the curve of thermal conductance of a glass piece inside a glass vial with 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 the same. If the aperture is adjustable and the curve is not fixed, then it could be curving as a result of the variation in the temperature of the glass used to create the bead, the temperature of the ambient air that is circulating on the inner surface of the vial, and the focal length and time of shooting. A signature left by a photographer on the petals of a flower is an example of a curly surface.
A lens and window must be mounted so that their focal points and lines of sight are correctly aligned. If the temperature of the inside of a system is too cold for the lens, then the outside temperature of the frame and the interior temperature will be too high. If the outside temperature of the lens and the frame are equal, then the frame will not require any adjustment to counteract the cooling or heating effects of internal temperature variations. If there are no temperature differences from outside, the frame’s inside temperature will be the same for a given focal length. If the system is situated in an area that has restricted or unobstructed views of surrounding structures or landscape it could be necessary to control the internal temperature.
The first mechanical interlocking system that was used to attach camera lenses were made out of plastic. This innovation was later adopted for use with pinhole glasses. A problem with this type of lens assembly is that the mechanical joints between the frame and the lens might indent or even fracture. If this happens the result will be necessary to replace the entire unit in a relatively short amount of time. Due to this, this type of system has been replaced by more robust designs.
Lenses designed to be used with pinhole glasses usually have frames made of metallic and a thin glass or plastic lid. At a minimum the lense designs must be sealed with a hermetically-sealed lens construction. A lens that is hermetically sealed has a sealed surface on the bottom and top. The top surface could have a similar seal as the one described above. Alternatively, it could also contain a different substance, such as an adhesive, lip, or a layer of plastic film.
Another variation of window and lens assembly is a lens surface that contains an adhesive that adheres to the base of the window assembly. This kind of system is typically comprised of a casing for windows and several compartments for lenses. Other types of devices could be used in the windows, for example, thermometers and light emitters. In some instances, the device used to regulate the temperature of the room could be part of this kind of system. In that case there are a number of compartments that could be used to house the temperature controller as well as a range of other devices, including an alarm thermostat or clock.
This is not a complete list of all kinds of window assemblies and lenses that are available. It’s an indication of the significant technologies that are connected to this invention. For more information, please look over the entire disclosure. In particular, please read the portions relating to “details of the present invention” and “Description of the Method with Regard to the Identification of the Different classes of products Involved in the Present Application.”
know more about lens and window here.