Because of the dependence of our thermal emission characteristics on the thermal wavelength, only a few wavelengths are suitable for measurements of thermal. The following graphs show the range of thermal transmission of the most common thermal lenses as well as window substances for infrared thermometers. The blue-colored curve shows the general rule applicable to all materials and represents the average value across an interval of temperature from 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 rate against the thermal gradient. This ratio is calculated as a function of the temperature variation along the viewing angle for given viewing angle and the cte of a window or lens. The slope of the curve is proportional to the bending force of an entire system, which is the result when the angle of incidence changes from linear to spherical. The focal length of a system is also an important factor in the slope. This is thought of as a function of the focal length divided by the period of the curve (i.e. the duration between shots).
The temperature of the inside of the system will always remain within the prescribed curve for a particular temperature and the focal length of the window assembly or lens. This is also known as a “curved top”. 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 the vial’s surface, and the angle of incidence for a specific window assembly. If the aperture is fixed for all shots, then the space between the 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 due to variations in the temperature of glass used to create the bead and ambient air temperature length of the lens, and time of photography. An example of a curved surface can be seen in the signature of the photographer of flowers.
A window and lens must be mounted in a way that their focal points and lines of sight are properly aligned. If the temperature of the inside of the system is too cold for the lens, then the outside surface temperature of the frame will be lower and the inside of the lens will be too hot. If the outside temperature of the lens and the frame are equal and the frame is at the same temperature, it will not require any adjustments to compensate for the cooling or heating effects of internal temperature variations. If there aren’t any temperature variations from outside, the system’s inside temperature will be the same for a given focal length. If the system is situated in an area with limited or obstructed views of surrounding buildings or scenery it might be necessary to control the internal temperature.
The first mechanical interlocking systems used to attach lenses to cameras were made of plastic or other materials that could change shape or bend according to changes in mounting pressure. This design was later adopted to work with pinhole glasses. This kind of lens assembly has a problem with the mechanical joints that connect the frame and lens could break or be indented. If this should be happening, it will be required for the entire assembly to be replaced in an extremely short amount of time. This is the reason why this system has been replaced with more durable designs.
Lenses made to be used with pinhole glasses usually have frames made of metal and an elongated glass or plastic lid. These lense designs should at the very minimum have a hermetically-sealed construction. A hermetically sealed lens construction includes a sealed surface at the bottom and top of the lens assembly. The top layer could be a part of a mechanical seal similar to the one previously mentioned. Additionally, it could contain a different substance, like an adhesive, a lip, or a layer of plastic film.
A lens surface that has the substrate and is attached to the base is an additional embodiment of this type window and lens assembly. This type of system typically consists of a window casing and several compartments for lenses. Other types of devices could be used in the windows, such as thermometers and light emitters. This kind of system may also include the thermostat or light emitter that controls the temperature in the room. In this case the system would comprise of compartments that could house the temperature controller along with a number of other devices, including an alarm thermostat or clock.
This is not an exhaustive list of all kinds of lens and window assemblies. It is however a good indication of the key technologies that are related to this invention. Please refer to the entire disclosure for more details. Particularly, 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 classes of products Included in the Present Applica.”
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