In this paper we report on new developments associated with SCD VOx μ-Bolometer product line. Lately, we have
introduced the BIRD6401,2, which is a high-sensitivity (< 50 mK @ F/1, 60Hz) VGA format detector with 25 μm pitch.
In the first part we present new data extracted from extensive measurements. These measurements were conducted
under various environmental and power constraints, exhibiting superior temporal sensitivity, long-term stability and
In the second part we describe the system implications of special features that were embedded within the FPA.
Explicitly, we will address the benefits of some special features aimed at lowering the system power dissipation while
maintaining low temporal and spatial NETD.
Finally, in the last part we outline SCD's future roadmap and development directions. We will elaborate on our latest
progress towards improved pixel sensitivity (25mK@F/1), advanced 0.18um ROIC technology, and the combination of
the two towards smaller pitch (17 μm) arrays.
In this paper we report preliminary data of BIRD640, which is a high-sensitivity (50 mK @ F/1, 60Hz) VGA format
detector with 25 μm pitch. This high performance is achieved by utilizing an improved pixel design. The product is
architecturally compatible to BIRD384 and contains SCD's proprietary unique features (e.g. "Power-Save", Ambient drift
The ROIC architecture follows the framework of the previous designs. It consists of an internal timing machine with a
single clock that facilitates the system interface. Extensive effort was invested in reducing the detector and system power
dissipation. The ROIC supports special "low power" modes, where considerable power is saved with only minor
With its superior temporal sensitivity, long-term stability and operational flexibility BIRD640 serves as an ideal
candidate for high end and high resolution uncooled VGA systems, particularly hand-held applications.
SCD has established an uncooled detector product line based on the high-end VOx μ-bolometer technology. The first
PFA launched was BIRD384, a 384x288 (or 320x240) configurable format with 25μm pitch. Typical NETD values for
these FPAs are below 50mK with an F/1 aperture and 60 Hz frame rate.
The product exhibits superior image uniformity, stability and reduced power consumption, making it most suitable for a
broad range of "high-end" military and commercial applications.
In this paper we report on our progress in development of new products in accordance with SCD's uncooled products
1. A "sensitive" version of BIRD384 with an improved NETD of ~ 30mK @ F/1, 60Hz frame rate. This
performance is achieved by optimizing concurrently the membrane structure, pixel architecture and ROIC
2. An improved version of BIRD384 ROIC that supports 100/120Hz frame rate and high dynamic range ("Fire Man" option).
3. First data of the BIRD640 - a 640x480 array with 25μm pitch and NETD ≤ 50mK @ F/1, 60Hz frame rate.
Last year SCD presented an un-cooled detector product line based on the high-end VOx microbolometer technology. The first PFA (BIRD384) launched was a 384x288 software configurable (to 320x240 or other) format with 25μm pitch1. NETD values for these FPAs are better then 50mK with an F/1 aperture and 60 Hz frame rate.
Since then SCD has concentrated in improving both spatial and temporal performance. In order to reduce the Residual
Non-Uniformity (RNU) and increase the time span between shutter operations, SCD has incorporated various features within the FPA and supporting algorithms2.
Improved temporal performance was achieved by optimizing concurrently the membrane structure and ROIC electronics. SCD has demonstrated temporal NETD of ~ 20mK @ F/1 at 30Hz on a 160x120 BIRD compatible array.
This figure of merit, accompanied by the superior stability and reduced power consumption, makes SCD's VOx based detectors suitable candidates for a broad range of "high-end" military and commercial applications.
SCD has recently presented an uncooled detector product line based on the high-end VOx bolometer technology. The first FPA launched, named BIRD - short for Bolometer Infra Red Detector, is a 384x288 (or 320x240) configurable format with 25μm pitch. Typical NETD values for these FPAs range at 50mK with an F/1 aperture and 60 Hz frame rate. These detectors also exhibit a relatively fast thermal time constant of approximately 10 msec, as reported previously.
In this paper, the special features of BIRD optimized for unattended sensor applications are presented and discussed.
Unattended surveillance using sensors on unattended aerial vehicles (UAV's) or micro air vehicles (MAV's) , unattended ground vehicles (UGV's) or unattended ground sensor (UGS) are growing applications for uncooled detectors. This is due to their low power consumption, low weight, negligible acoustic noise and reduced price. On the other hand, uncooled detectors are vulnerable to ambient drift. Even minor temperature fluctuations are manifested as fixed pattern noise (FPN). As a result, frequent, shutter operation must be applied, with the risk of blocking the scenery in critical time frames and loosing information for various scenarios.
In order to increase the time span between shutter operations, SCD has incorporated various features within the FPA and supporting algorithms. This paper will discuss these features and present some illustrative examples.
Minimum power consumption is another critical issue for unattended applications. SCD has addressed this topic by introducing the "Power Save" concept. For very low power applications or for TEC-less (Thermo-Electric-Cooler) applications, the flexible dilution architecture enables the system to operate the detector at a number of formats. This, together with a smooth frame rate and format transition capability turns SCD's uncooled detector to be well suited for unattended applications. These issues will be described in detail as well.
SCD has recently presented an un-cooled detector product line based on the high-end VOx bolometer technology1. The
first PFA launched, BIRD, is a 384x288 (or 320x240) configurable format with 25μm pitch. Typical NETD values for
these FPAs range at 50mK with an F/1 aperture and 60 Hz frame rate. These detectors also exhibit a relatively fast
thermal time constant of approximately 10 msec.
In this paper we elaborate on the special advanced features that were incorporated within the ROIC and supporting
algorithms. In this framework we have addressed two important issues: the power consumption and the time span
between shutter activations. Minimum power consumption is a critical issue for many un-cooled applications. SCD has
addressed this by introducing the "Power-Save" concept accompanied with flexible dilution architecture. The paper will
present recent results exhibiting the various advantages.
One of the limiting factors on the performance of un-cooled detectors is their vulnerability to ambient drift. Usually,
even minor temperature fluctuations are manifested as high residual non-uniformity (RNU) or fixed pattern noise (FPN).
As a result frequent shutter operations must be applied, with the risk of blocking the scenery in critical time frames. The
challenge is thus twofold: increase the time span between shutter corrections and achieve better control of its activation.
For this purpose BIRD provides two complementing mechanisms: A real-time (frame-by-frame) ambient drift compensation accompanied by an RNU prediction mechanism. The paper will discuss these features in detail and present illustrative system implementations.
SCD is unveiling the first member of its new uncooled product line based on the high-end VOx technology. The detector is software configurable to various format standards including 384x288, 320x240 and others with 25μm pitch. The NETD values for these FPAs are better then 50mK with F#/1 aperture and 60 Hz frame rate. These detectors also exhibit a relatively fast thermal time constant of approximately 10msec. In order to improve the system level "cost-performance" in terms of power consumption and weight, SCD has introduced special features within the FPA & package. Among them is a proprietary "Power Save" architecture, in which the die temperature can be stabilized to the ambient temperature or a close enough discrete value, covering the range between -40c and 70c. Thus, the TEC power consumption is considerably reduced with minimal performance degradation. An additional benefit is improved "mission readiness" which is of vital importance for various system applications. A major limitation of systems based on uncooled detectors is the poor resilience to the ambient temperature drift. This drift degrades the spatial non-uniformity. As a result, frequent corrections using an optical shutter are required, specifically during the camera stabilization period. In order to increase the time span between shutter operations, SCD has incorporated various real-time monitoring features within the FPA and supporting algorithms. These features reduce the spatial noise by an order of magnitude.
In this paper we present a long Infrared Detector (LIRD) with Time Delayed Integration (TDI) mechanism in the 3mm - 5mm spectral band. The detector consists of four segments that are 'butted' on a single substrate in a staggered format. A novel butting technique ensures high accuracy and extremely uniform temperature distribution along the array. Each detector segment (DS) consists of an advanced CMOS readout integrated circuit (ROIC) attached to a back-illuminated diode array. The diode array is implemented with SCD's proprietary high performance InSb process. The ROIC is designed and optimized to be used with high F#, 'slow scan rate' systems. Very low power dissipation is emphasized. In order to achieve high flexibility, the signal processor is externally programmable, enabling TDI operation with or without over-sampling on any combination of elements. Some other features include: Bi-directional operation, defective pixel de-selection, variable line rates and integration times, externally controlled gain and background subtraction capability. The paper presents electrical and radiometric predictions. Measured results that were performed on the first prototype are also presented.
The transition to second generation backside-illuminated dense LWIR FPAs requires consideration of issues not previously relevant in first generation modules: unlike in front illuminated arrays, the MTF (or effective area) of a pixel is no longer close to the ideal sinc function. The cutoff wavelength, quantum efficiency and crosstalk depend on the thickness and composition grading of the epitaxial layer. The tradeoff between resolution and sensitivity demands extensive engineering and optimization of the array configuration. The transition was accomplished by comparisons of simulations with experimental results. Expectations of performance indicators, such as MTF, quantum efficiency and crosstalk were obtained by detailed Monte-Carlo simulations. The results were used to configure the focal plane array. This paper discuses the basic assumptions and simulation results and compares them with the performance of actual detectors and various test structures.