Due to the high dependence of our thermal emission behavior on the wavelength of the thermal radiation that we have, only certain wavelengths are suitable for thermal measurements. The following graphs show the range of thermal transmission of standard thermal lenses and window substances for infrared thermometers. The blue-colored curve represents the general rule for all materials. It is the average value over the temperature range from zero (black) and infinity (green), and that is the cold-pressure limit (CPL).
For lenses and windows The cold-pressure limit can be defined as the maximum measured value of the damping ratio of a material against the thermal gradient. This ratio is calculated as a function the temperature variation along the angle of view 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 spherical or linear. This makes the slope proportional to the curve. The slope of this curve is also proportional to the focal length of the 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 given set of temperatures and a certain focal length of a window or lens assembly, the inside temperature of the system will always fall within the prescribed curve in an exact regularity, also known as a “curved surface.” For instance the curve of thermal conductance of a glass bead inside a glass vial with holes in it could be plotted as a function of the focal length, the temperature difference inside the vial between the bottom of the bead and its surface, and the angle of incidence for a given window assembly. If the aperture is fixed for all shots, then the area between the system’s surface temperature and the curve of variation must remain constant. Variable apertures can cause the curve to become curvilinear due to variations in the temperature of glass used to make the bead as well as the ambient air temperature, focal length, and time of photography. A signature left by a photographer on a flower is an example of a curved surface.
A window and lens must be mounted in a way that their focal points and lines of sight are correctly aligned. If the interior surface temperature of an object is too cold for the lens, the exterior temperature of the frame and its interior temperature will be too high. When the outside temperature of the lens and the frame are the same and the frame does not require any adjustments to counteract the heating or cooling effects of internal temperature variations. If there are no temperature variations from outside, then the system’s inside surface temperature will be the same for a particular focal length. If the system is situated in an area that has limited or obstructed views of surrounding structures or landscape, it may be necessary to control internal temperatures.
The first mechanical interlocking systems used to secure lenses onto cameras were made of plastic or other materials that would bend or mold depending on changes in mounting pressure. This innovation was later adopted to work with pinhole glasses. This kind of lens assembly has a problem that the mechanical joints between the lens and frame might crack or indent. If this were to happen the result would be required to replace the entire system within a short amount of time. This is why this system is being replaced with more durable designs.
Pinhole glasses lenses are generally constructed with a frame made of metal and a thin, plastic or glass lid. These lense designs must at a minimum, have a hermetically sealed construction. A hermetically sealed lens has a sealed surface on the bottom and the top. The top layer could be a part of an electronic seal similar to that previously mentioned. It could also be a source of adhesive, lip or a layer of plastic film.
Another embodiment of this type of window and lens assembly is a lens surface that contains a substrate, which adheres to the base of the window assembly. This type of system is typically comprised of a casing for windows and several compartments for the lens. The windows may also contain other kinds of devices, like light emitters or thermometers. In certain instances, the device used to regulate the temperature of the room could also be part of this kind of system. In this case the system would comprise of compartments that could house the temperature controller along with a number of other devices, like an alarm clock or thermostat.
This isn’t an exhaustive list of all kinds of window and lens assemblies. It’s an indication of the significant technologies that are connected to this invention. Please refer to the entire disclosure for more details. In particular, please look over the sections that pertain to “details of the Present Invention” and “Description of the Process with Regard to the Identification of the Various classes of products Involved in the Present Application.”
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