500-0763-01

FLIR LEPTON® with Radiometry Datasheet Document Number: 500-0763-01-09 Rev 110 General Description Lepton® with Radiometry is a complete longwave infrared (LWIR) camera module designed to interface easily into native mobile-device interfaces and other consumer electronics. It captures infrared radiation input in its nominal response wavelength band (from 8 to 14 microns) and outputs a uniform thermal image with radiometry to provide temperature image with measurements.  Features            Integral shutter configuration: 11.5 x 12.7 x 6.9 mm (without socket) 11.8 x 12.7 x 7.2 mm (with socket) 50° HFOV, 60° diagonal (f/1.1 silicon doublet) LWIR sensor, wavelength 8 to 14 µm 80 (h) × 60 (v) active pixels Thermal sensitivity 185 msec) following a CRC error. The following figures are examples of violations that result in a loss of synchronization. Figure 28 - Valid Frame Timing (no loss of synchronization) Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 56 FLIR LEPTON® with Radiometry Datasheet Figure 29 -Clock Too Slow - Failure to Read an Entire Frame Within the Frame Period Figure 30 - Intra-frame Delay Too Long - Failure to Read Out an Entire Frame Before the Next is Available Figure 31 - Failure to Read Out an Available Frame 8.2.3 Frame Synchronization The VoSPI protocol is designed such that embedded timing signals are not required. However, the Lepton does provide an optional frame-timing output pulse that can aid in optimizing host timing. For example, the host can burst-read data at a high clock rate and then idle until the next frame-timing pulse is received. The pulse is enabled by selecting the VSYNC GPIO mode via the CCI; when enabled, it is provided on the GPIO3 pin (see GPIO Modes, page 43). The signal can be configured (also via the CCI) to lead or lag the actual internal start-of-frame (that is, the time at which the next frame is ready to be read) by -3 to +3 line periods (approximately -1.5 msec to +1.5 msec). By default, the pulse does not lead or lag. Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 57 FLIR LEPTON® with Radiometry Datasheet 9.0 Thermal Camera Basics It is noteworthy that the integration period for a thermal detector does not have the same impact on image formation as it does for a photon detector, such as a typical CMOS array. While a photon detector converts incoming photons to electrons with near-instantaneous response a microbolometer such as the Lepton is always integrating incident radiation. That is to say, it is always “active” regardless of whether or not it is being actively integrated. The ability to detect high-speed phenomena is more a function of the detector's thermal time constant, which governs the rate of temperature change. For Lepton, the detector time constant is on the order of 12 msec, which means that an instantaneous irradiance change will result in a temperature change of the detector as shown in Figure 32. Figure 32 - Illustration of Lepton Detector Time Constant In addition to integrating signal current, the ROIC also digitizes and multiplexes the signal from each detector into a serial stream. And the Lepton ROIC digitizes data from an on-chip temperature sensor as well as a thermistor attached to the camera housing. An anti-reflection (AR) coated window is bonded above the sensor array via a wafer-level packaging (WLP) process, encapsulating the array in a vacuum. The purpose of the vacuum is to provide high thermal resistance between the microbolometer elements and the ROIC substrate, allowing for maximum temperature change in response to incident radiation. Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 58 FLIR LEPTON® with Radiometry Datasheet 10.0 Mounting Specifications The Lepton camera mounting dimensions are shown Figure 33 Figure 33 - Lepton with Radiometry Camera Mounting Dimensions Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 59 FLIR LEPTON® with Radiometry Datasheet 11.0 Socket Information The Lepton module is compatible with two commercially-available sockets, Molex 105028-1001 and Molex 105028-2031, illustrated in Figure 34 below. The former makes electrical contact on the upper surface of a printed circuit board, the latter to the lower surface (with a cutout in the board that allows the socket to fit into). In both cases solder connections are made to the top or “component” side of the board. Figure 35 depicts both socket configurations mounted on a PCB. To order sockets, visit www.arrow.com. Figure 34 - Two Commercially-available Sockets (both from Molex) Compatible with Lepton Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 60 FLIR LEPTON® with Radiometry Datasheet Figure 35 - Both Sockets Mounted on a PCB Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 61 FLIR LEPTON® with Radiometry Datasheet 11.1 Mechanical Considerations The socket described in Socket Information on page 60 is not intended to retain the Lepton assembly under high-shock conditions. It is recommended to incorporate front-side retention such as illustrated in Figure 36. Note that a maximum, uniform, load of 1KgF can be applied to the shutter face without causing failures in shutter actuation. Figure 36 - Recommended Approach to Retaining Lepton in the end Application The Lepton camera is not a sealed assembly. Consequently, for most applications it is recommended to locate the assembly behind a sealed protective window. Common materials for LWIR windows include silicon, germanium, and zinc selenide (LWIR absorption in silicon is on the order of 15%/mm, which means NEDT is adversely affected using a silicon window. Bulk absorption in germanium and zinc selenide is negligible, and performance is essentially unchanged provided both surfaces of the window are anti-reflection (AR) coated.) Note that the window should be sized large enough to avoid encroaching upon the optical keepout zone (see Optical Considerations, page 63). Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 62 FLIR LEPTON® with Radiometry Datasheet 11.2 Thermal Considerations It is important to minimize any temperature gradient across the camera. The sensor should be mounted in such a fashion so as to isolate it from heat loads such as electronics, heaters, and non-symmetric external heating. The surrounding area must be able to support and withstand the dissipation of up to 160 mW of heat by the camera. 11.3 Optical Considerations The optical keepout zone is described by the three dimensional field of view cone within the Lepton with Radiometry STEP file. To avoid mechanical vignetting, do not impinge upon the keepout zone defined by this cone. Information on this page is subject to change without notice. 500-0763-01-09, Lepton with Radiometry Datasheet, Rev: 110 63 FLIR LEPTON® with Radiometry Datasheet 12.0 Image Characteristics The information given in Table 15 applies across the full operating temperature range. Table 15 - Image Characteristics Parameter Description Value NETD Noise Equivalent Temperature Difference (random temporal noise) 99.0% Number of adjacent defective pixels N/A2 (