Advances in infrared (IR) focal plane arrays (FPA) have steadily encroached upon the limits of technology. Larger formats, smaller detectors, and higher operability have improved performance. The next step is an FPA that accepts photons and converts them into a corresponding digital word. This advancement reduces susceptibility to electromagnetic interference (EMI) at the interface and minimizes the complexity of the downstream electronics. Attempts to integrate this function in an FPA involved technical difficulties such as increased power, low resolution, and non-linearity. Santa Barbara Focalplane has successfully developed a number of different types of digital FPAs with improved performance and lower power than equivalent analog FPAs. These FPAs have been integrated into closed-cycle dewar-cooler assemblies (IDCA) and are being shipped in production quantities.
The advanced planar ion-implantation-isolated heterojunction process, which utilizes the benefits of both the boron implantation and the heterojunction epitaxy techniques, has been developed and used to produce longwave and very longwave HgCdTe focal plane arrays in the 320v256 format. The wavelength of these arrays ranges from 10.0-17.0μm. The operability of the longwave HgCdTe arrays is typically over 97%. Without anti-reflection coating and with a 60° FOV cold shield, the D* of the 10.0μm array is 9.4x1010cm x (Hz)1/2 x W-1 at 77K. The 14.7μm and 17.0μm very longwave HgCdTe array diodes have excellent reverse characteristics. The detailed characteristics of these arrays are presented.
A theoretical design of a reconfigurable detector array assembly is presented. This device is capable of changing the angular resolution and thermal sensitivity of the electro- optics array in real time. The apparent layout (i.e., size, spacing, and location) of the focal plane array detector elements is dynamic. This approach allows varying the instantaneous field-of-view as a function of the field angle, and combining adjacent spectral bands when poor atmospheric conditions are presented. This infrared reconfigurable hyperspectral focal plane array (IR-RHFPA) provides a way to get rid of some of the problems related to multi-spectral imagery sensors such as data rate, bow-tie effect, and sensitivity. Curves of spatial resolution versus field angle, and thermal sensitivity versus wavelength are obtained for the proper design and optimization of the IR-RHFPA. The potential operational configurations that best satisfy the system requirements are identified and displayed.
Santa Barbara Focalplane has recently added a versatile large- format MWIR camera to its product family. The camera features a dynamically moveable window ranging in size from 128 X 8 (greater than 4 KHz frame rates) up to 640 X 512 (120 Hz frame rates) with an 8 pixel resolution. This paper addresses the FPA architecture along with various performance parameters, noise, resolution issues, and some early measurements.
Modern focal plane arrays (FPAs) are being driven to lower cost, higher resolution, and more features. The complexity and requirements of such FPAs overwhelm traditional design approaches. An all encompassing design methodology that includes the requirements process, a tightly integrated test capability, an extensive modeling capability, and a detailed understanding of the foundry and FPA fabrication processes is required. Santa Barbara Focalplane's overall design methodology is presented as an approach to managing current and future FPA complexity.
The ImagIR infrared imaging system along with image based test methods has been used as a primary approach for evaluating focal plane array performance at Santa Barbara Focalplane (SBF). This information has been used to provide feedback to the in-house processing line as part of the SBF continuous measurable improvement program. Recently, the testing capabilities at SBF have undergone significant expansion through an elegant integration of the ImagIR systems with other commercially available software and hardware. The resultant test set contains a new powerful test environment where system imagery and traditional radiometric figures of merit are readily available for evaluation and correlation. Key features of this environment include a user friendly interface, flexibility, and low development, replication, modification, and maintenance costs.