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 diagrams illustrate the range of thermal transmission of the most common thermal lenses as well as window materials for infrared thermometers. The blue-colored curve illustrates the general rule for all materials and shows the average value over an interval of temperature from zero (black) to infinity (green) that is the cold-pressure limit (CPL).
For windows and lenses, the cold-pressure limit is defined as the highest value of the damping ratio of a material in relation to the thermal gradient. This ratio is calculated as a function the temperature difference along the viewing angle for given viewing angles and cte of a lens or window. The bending moment of a system is the variation in angle of incidence from linear or spherical. This makes the slope proportional to this curve. The focal length of a system is also an element in the slope. It can be thought of as a function of the focal length divided by the length of the curve (i.e. the duration between shots).
For a particular set of temperatures and a given focal length of a window or lens assembly, the inside temperature of the system will always fall within the prescribed range in an exact regularity, also called a “curved surface.” The thermal conductance curve of a glass bead inside a glass vial could be plotted as a function of the focal length, the temperature difference between the bottom of the vial and its surface and the angle of incidence of a particular window. If the aperture is fixed for all shots, then the area between the inside surface temperature of the system and the curve of variation for the particular window assembly should always remain constant. Variable apertures can cause the curve to become curvilinear because of variations in the temperature of glass used to make the bead and ambient air temperature the focal length, and the time of photography. A signature left by photographer on flowers is an example of a curving surface.
The mounting of a window and lens must be done to ensure that their focal points, and lines of sight are correct. If the inside surface temperature of the system is too hot for the lens, then the outside surface temperature of the frame will be lower and the interior temperature of the lens will be too hot. When the outside temperature of the lens and the frame are the same and the frame is at the same temperature, it will not require any adjustments to counteract the effects of heating or cooling of internal temperature differences. The inside temperature of the system will be correct for a particular focal length without the need for any other adjustments, provided that there is no external cause of temperature variations affects the system. If the system is situated in an area that has limited or obstructed views of surrounding buildings or scenery, it may be necessary to control the internal temperature.
The first mechanical interlocking system used to mount lenses to camera were made from plastic. This design was later used to create pinhole glasses. The issue with this kind of lens assembly is that the mechanical joints between the frame and lens might indent or even fracture. In the event of this occurring, it would be essential for the entire system to be replaced within an extremely short amount of time. Because of this issue the type of system has been replaced with more robust designs.
Pinhole glasses lenses are generally constructed using a frame of metal and a thin, glass or plastic lid. At the very least the lense designs should be sealed with 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 may contain an electronic seal that is similar to that previously mentioned. Additionally, it could contain some other substance, such as an adhesive, lip, or a layer of plastic film.
Another variant of lens and window assembly is to have a lens surface that contains a substrate, which adheres to the base of the window assembly. This type of system usually consists of a casing for windows and a series of compartments for lenses. Other types of devices could be integrated into the windows, for example, light emitters and thermometers. This type of system could include a thermostat or light emitter that regulates the temperature in the room. In this case the system would comprise of compartments that could be used to house the temperature controller together with a variety 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. However, it does provide an indication of the key technologies that are associated with this invention. For more information, look over the entire disclosure. In particular, you should look over the sections that pertain to “details of the Present Invention” and “Description of the Method with Respect to the Identification of the Various Classes of Products That Are Included in the Present Applica.”
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