Browsing by Subject "Microbolometer"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Methods to achieve wavelength selectivity in infrared microbolometers(2007-05) Jung, Joo-yun, 1976-; Neikirk, Dean P., 1957-A simple Salisbury Screen structure has been adopted for conventional infrared microbolometer, which is usually designed to detect only one infrared band. Dielectric coated Salisbury Screen modified from the Salisbury Screen successfully shows narrow wavelength band absorption in a given wavelength range that is required for hyperspectral imaging. An approach for designing simple Salisbury Screen for broad band and Dielectric coated Salisbury Screen for wavelength selectivity is presented. Calculations of electromagnetic behaviors of designs and verification are presented. Additionally, Dielectric coated Salisbury screen without air gap and simple Salisbury Screen with dielectric spacer layer are fabricated, and the spectral response of those devices are measured. Comparison between simulated and measured data of these devices are presented and discussed. Finally, the narrow wavelength band absorption of the patterned resistive sheets in LWIR is presented for future work.Item Methods to achieve wavelength selectivity in infrared microbolometers and reduced thermal mass microbolometers(2010-12) Jung, Joo-Yun, 1976-; Neikirk, Dean P., 1957-; Bank, Seth; Belkin, Mikhail; Hall, Neal; Rogers, Robert L.The use of a patterned resistive sheet as an infrared-selective absorber, including the effects of a mechanical support dielectric layer is discussed. Also, modified dielectric coated Salisbury Screen can improve both the wavelength selectivity and the speed of thermal response for microbolometers. These patterned resistive sheets and Modified dielectric coated Salisbury Screen are a modified form of classical Salisbury Screens that utilize a resistive absorber layer placed a quarter-wavelength in front of a mirror. These structures can show a narrower detection bandwidth when compared to conventional microbolometers. For a Modified dielectric coated Salisbury Screen for multi-spectral system, wavelength selectivity can be varied by changing the distance to the mirror, and for patterned resistive sheet, wavelength selectivity can be varied by changing the lithographically drawn parameters of the array. Hence, different pixels in a focal plane array can be designed to produce a “multi-color” infrared imaging system. Also, the thermal mass of microbolometer is reduced using patterned resistive structure.Item Patterned resistive sheets for potential use in 3D stacked multispectral reduced thermal mass microbolometer(2013-12) Kim, Hoo; Neikirk, Dean P., 1957-Patterned resistive sheets (PRS) are resistive sheets with periodic patterns which provide further advantages to the functionality of the microbolometer. This study examines the potential of both single- and double-layer designs to achieve spectral selectivity in both broadband and narrowband absorption in the microbolometer's application. First, important design parameters, including rules and processes, are established. These include descriptions of sheet resistance, air gap, material refractive index, thicknesses of dielectric and bolometric layers, mirror, pattern shape and size, and unit cell period. Moreover, interactions among these elements are examined. Second, single-layer designs using dipole and slot PRS are introduced as initial designs for the reduced thermal mass design. Applying holes without changing spectral selectivity are investigated for narrowband application. Moreover, the method to tune the change of spectral selectivity is introduced. Third, newly stacked two-color design is suggested. The out-of-band transmission and reflection characteristics of the dipole and slot PRS are investigated to increase the absorption of each layer. Additionally, different pattern shapes, such as the circular patch and square patch, are investigated for easier fabrication.