Due to the high dependence of our thermal emission behaviour 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 reveal the thermal transmission range of standard thermal lenses and window materials for infrared thermometers. The blue-colored curve demonstrates the general rule for all materials, and represents the average value for a temperature interval of zero (black) to infinity (green), which is the cold-pressure limitation (CPL).
For windows and lenses the cold-pressure limit is defined as the highest value of the damping ratio of a material against the thermal gradient. This ratio is plotted as a function the temperature difference across the angle of view for a specific viewing angle and the cte of the lens or window. The bending moment of a system is the change in angle of incidence from linear or spherical. This results in the slope being proportional to this curve. The focal length of a system is also an element in the slope. This can be considered as a function of the focal length divided the period of the curve (i.e. the interval between shots).
For a particular set of temperatures and a specific focal length of a window or lens assembly, the inside temperature of the system will always fall within the prescribed range in a perfect regularity called a “curved surface.” For instance the curve for the thermal conductivity of a glass beads inside a glass vial having holes in it could be plotted as a function of the focal length and 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 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 should remain constant. If the aperture is variable this means that the curve could be curved because of the variations in the temperature of the glass used in the making of the bead and the temperature of the ambient air that is circulating on the inner surface of the vial and the focal length and duration of shooting. A signature left by a photographer on flowers is an example of a curving surface.
A lens and window must be mounted in a way that their focal points and lines of sight are properly aligned. If the interior surface temperature of the system is too cold for the lens, the exterior temperature of the frame as well as the interior temperature will be too high. The frame will not need to be adjusted to account for internal temperature fluctuations or cooling effects. If there are no temperature variations from outside, then the system’s internal temperature will be the same for a given focal length. If the system is situated in an area with restricted or blocked views of the surrounding scenery or buildings it could be necessary to control internal temperatures.
The first mechanical interlocking system used to attach lenses to cameras were constructed of plastic or other materials that could change shape or bend according to changes in mounting pressure. This design was later adopted for use with pinhole glasses. One issue with this type of lens assembly is that the mechanical joints between the frame and the lens might indent or even fracture. In the event of this occurring, it would be essential for the entire system to be replaced within the shortest amount of time. This is why this system has been replaced with more durable designs.
Lenses designed for use with pinhole glasses typically come with frames made of metallic and an elongated glass or plastic lid. At the very least, these lense designs should include a hermetically sealed lens construction. A hermetically sealed lens construction has a sealed surface on the bottom and the top. The top layer could be a part of an electronic seal similar to that described above. It could also contain an lip, adhesive, or layer of plastic film.
A lens surface that is the substrate and is attached to the base is another embodiment of this type window and lens assembly. This type of system is typically comprised of a casing for windows and a series of compartments for the lens. The windows could also include other kinds of devices, such as light emitters or thermometers. In certain instances, the device that controls the temperature of the room might also be part of this kind of system. A number of compartments could be used to house the temperature controller and a variety of other devices like an alarm clock, thermostat, or other devices.
This is not a complete list of all kinds of window and lens assemblies that are available. It’s a good indication of the important technologies related to this invention. Please read the entire disclosure for more information. Refer to the sections that pertain to “details regarding the present invention” and “Description of the Method with Respect To the Identification of the various classes of products which are involved in the Present Application.”
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