Due to the high 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 effective for thermal measurements. The following figures show the range of thermal transmission for common thermal lenses and window materials for infrared thermometers. The blue-colored curve reflects the general rule for all materials. It is the average value over the temperature range of zero (black) to infinity (green) and is the cold pressure limit (CPL).
The cold-pressure limit, which is used for lenses and windows is the highest measured value of a material’s damping coefficient against the thermal gradient. This ratio is plotted as a function the temperature differential across the viewing angle for a given viewing angle and cte for the lens or window. The bending moment of a system is the change in angle of incidence from spherical or linear. This makes the slope 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 length of the curve (i.e. the period between shots).
For a particular temperature range and a certain focal length of a window or lens assembly, the internal surface temperature of the system will always be within the prescribed curve in an exact regularity, also known as a “curved surface.” For instance the curve for the thermal conductance of a glass bead inside a glass vial having a hole in it can be plotted in relation to the focal length and the temperature difference inside the vial between the bottom of the bead and its surface, and the angle of incidence for a particular window assembly. If the aperture is fixed for all shots then the area between the system’s surface temperature and the curve of variation will remain the same. Variable apertures can cause the curve to become curvilinear because of variations in the temperature of the glass used to create the bead as well as the ambient air temperature, length of the lens, and time of photography. A signature left by photographer on a flower is an example of a curving surface.
Mounting a lens and window should be done so that their focal points, and lines of sight, are in the correct direction. If the temperature of the inside of a system is too cold for the lens, the outside temperature of the frame and its interior temperature will be too high. The frame won’t need to be adjusted in order to compensate for internal temperature variations or cooling effects. If there are no temperature variations from outside, the frame’s internal temperature will be the same for a given focal length. If the system is located in an area with restricted or unobstructed views of surrounding scenery or buildings it could be necessary to control internal temperatures.
The first mechanical interlocking system used to mount lenses to camera were made out of plastic. This innovation was later adopted to work with pinhole glasses. The issue with this kind of lens assembly is that the mechanical joints between the lens and frame might indent or even fracture. If this were to happen the result would be necessary to replace the entire system in a relatively short period of time. Because of this issue 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 include a hermetically sealed lens construction. A lens that is hermetically sealed has an enclosed surface at the bottom and top. The top surface may have a similar mechanical seal similar to that mentioned earlier. Alternatively, it could also contain some other substance, for instance, an adhesive, lip, or a layer of plastic film.
A lens surface that contains an adhesive and is bonded to the base is a different embodiment of this type window and lens assembly. This type of system typically comprises glass casings and series lens compartments. The windows may also contain other types of devices, such as light emitters or thermometers. In some cases, the device used to regulate the temperature of the room might also be part of this kind of system. A series of compartments could be used to house the temperature control and a variety of other devices like an alarm clock, thermostat, or other devices.
This is not an exhaustive list of all types of lens assemblies and windows. However, it is indicative of the key technologies that are related to this invention. Please refer to the complete disclosure for more information. In particular, you should take a look at the sections relating to “details of the Present Invention” and “Description of the Process with Respect to the Identification of the Different types of products Involved in the Present Application.”
know more about chalcogenide glass here.