Gaskets, tapes and adhesives can be applied to Dontech optical filters, film, and display assemblies to improve optical, mechanical and environmental performance. Gaskets and tapes help mount, seal and terminate the optical filter to the higher level display or touchscreen assembly and can be used in conjunction with one another or independently depending on the application.
Tapes are typically provided as 4 strips or die cut to size (e.g., picture frame). They are placed around the perimeter of the optics, so the outer release liner can be removed, allowing the window to be easily mounted to the display, frame, or bezel. They can be provided with single or double-sided adhesives. When utilized properly, they are an easy method to effectively perimeter mount optics.
Die cut tapes are typically selected when the tape is needed for an environmental seal. In these cases, a very high bonding, double-sided adhesive is typically used to bond the filter to the display, bezel, or frame. The tape can also be electrically conductive, however conductive tapes lack the bonding performance of nonconductive tapes. When the optical filter is being used to provide EMI/RFI shielding over the optical aperture, a conductive tape can be used to terminate the optical filter with the rest of the Faraday cage. In some cases, two parallel tapes will be used to optimize all properties.
Types of gaskets include environmental, conductive, or a combination (e.g., gaskets with both environmental and conductive properties). Mechanical form factors, EMI/RFI attenuation levels, and environmental requirements dictate gasket selection. Gasket material can be sized into a variety of shapes and thicknesses and attached to the filter perimeter via pressure sensitive adhesives, epoxies, and silicones. Additionally, conductive and nonconductive gaskets can be formed in place by applying the material directly to the optics or mounting assembly in a thixotropic form and then cured. Dontech gasket materials include:
Generally function to seal against moisture and dust. They may also be used to reduce shock and vibration in an assembly. Dontech most commonly uses neoprenes, silicones, and urethanes for environmental gaskets. These materials are available with a range of physical properties for compliance with many different applications, as well as many military standards.
Are primarily used to minimize transfer impedance between conductive ground planes and to provide a continuous electrical seal between conductive EMI/RFI shielding filters and the mounting surface of the shielded enclosure. Conductive gaskets can be comprised of metal (e.g., knitted wire mesh, spring fingers, metal helicoils), conductively loaded form-in-place, strip or die cut elastomers, tapes, and fabric-over-foam materials. EMI/RFI shielding is improved by minimizing the transfer impedance at the interface between the filter and the enclosure or bezel. Consequently, mechanical, electrical, galvanic, and thermal properties, as well as bus termination must be considered to optimize the performance of conductive gaskets.
Are used to provide an electrical and environmental seal between the filter and enclosure. Two common configurations are gaskets with conductive elastomers (e.g., silver-loaded silicone) and parallel environmental and conductive gaskets, which have a strip of conductive gasket attached to a strip of nonconductive elastomer.
Dontech has extensive engineering and technical support resources that can assist you with your tape and gasket design needs. Our technical staff have diverse backgrounds relevant to high-performance display and precision optics markets. For many of our top customers, we function as an extension of their engineering departments, supporting projects from concept to final system delivery. We will integrate our optical filters and other enhancing components into touchscreens , displays, and systems to the level that is needed by our customers.