Dielectric coating

Unilver Table 1. Worldwide 1992 Electronics Industry Value/ x 10 adhesives, dielectric coatings, protective coatings, dielectric interlayers, electronic functional coatings... 

The thickness of the dielectric coating on individual elements is nearly double the above... 

Keywords dielectric coatings, metallic coatings, deposition, ion beam sputtering, ion as-... 

To summarize this section about dielectric coatings, let us recall their advantages and drawbacks. Advantages are ... 

But metallic coatings have high absorption losses. But one can remedy them with dielectric coatings, which are necessary also to passivate the metal, avoiding oxidation. Aluminum is the best metal for the ultraviolet in addition it adheres on most substrates it needs passivation. Silver is easy to deposit it has the highest reflectance in the visible and the infrared since it tarnish rapidly, passivation is mandatory. Gold is the best material beyond 700 nm, and it is considered that it does not tarnish, which is not true actually because its surface is not that stable on the long term. 

Because of the series capacitor and/or the dielectric coating of the electrodes, the negative potentials established on the two electrodes in a plasma system may not be the same. For instance, the ratio of the voltages on the electrodes has been shown to be dependent upon the relative electrode areas (77). The (theoretical) dependence is given by Equation 1, where V is the voltage and A is the area (7d). 

Polished aluminum reflects radiation energy in the visible and infrared (IR) energy spectral regions at least as efficiently as in the UV region.1617 This is undesirable in cases where the substrate or the piece being irradiated is heat sensitive. To overcome this, the surface of the reflector is coated with special dielectric coatings... 

Steel with cathodic protection, using either dielectric coating, field installation by a corrosion expert, or impressed current system. 

The actual temperature increase is more moderate because the BP filter head is covered with the collection fiber, another metal tube, and the protection coat. We also tried to deposit a dielectric coating directly on the distal end of the optical fiber. Several dozen fibers were held separately in a holder that was inserted into the deposition chamber and the filter was deposited with the usual process. In this experiment, the filter was successfully deposited on the end face of the fibers, but its properties were not constant. This seems to be ascribable to a localized thermal irregularity in the deposition chamber, which affected the temperature of the end face of the individual fibers. The low quality of the deposited filter at the circumference of the fiber end was also a problem. It seems that the layer structure of the filter membrane at the edge of the fiber end face was in disorder and this portion got into the core part. The thickness of the cladding was only 5.5 pm in our fiber. It may be possible to avoid this problem by employing a thicker fiber. 

The main application of amorphous perfluoropolymers is as cladding of optical fibers, antireflective coatings, low dielectric coatings, and in the electronic industry (e.g., photoresists)1012 and as a low-dielectric-constant insulator for high-performance interconnects.13... 

However, in an attempt to integrate the SFA and spectroscopic techniques, the use of silver for optical interferometry has been seen as a drawback due to the fact that it precluded sufficient excitation source intensity to illuminate the buried interface. In order to circumvent this problem Mukhopadhyay and co-workers in an experimental set-up where the SFA was combined with fluorescence correlation spectroscopy (FCS) used, instead of silver, multilayer dielectric coatings that allowed simultaneous interferometry and fluorescence measurements in different regions of the optical spectrum [75]. Using this set-up they succeeded in measuring diffusion in molecularly thin films with singlemolecule sensitivity. 

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