Objective Infrared detection technology finds applications in various fields such as medical detection,meteorological detection,space remote sensing,national defense,and military.It converts infrared radiation signals into electrical signals and offers advantages like strong anti-interference capabilities and a wide detector range.In comparison to traditional detection technology,infrared detection technology is better equipped to handle complex and ever-changing environments.The advancement of space infrared detection technology has led to increased demands for infrared detection performance.As a result,large-area array and long-line array infrared detectors have emerged as the future direction of infrared detector development.This article focuses on the research of 2 k×2 k detectors,analyzing the characteristics and challenges associated with packaging technology for large-area array detectors.It also proposes corresponding solutions and methods. Methods The suppression of the infrared system's own radiation is crucial for ensuring the imaging quality of the optical system.This study analyzes the impact of the self-radiation of key surfaces in the Dewar component on the stray light of the detector.To reduce the stray light of the large-area array detector,low-temperature optics are employed in the design of the Dewar window(Fig.2).The study also examines the effect of Dewar window deformation on the imaging quality of the optical system under three different working conditions(Fig.4).Additionally,the research investigates the impact of the cold platform's structural design on noise suppression in detection,and evaluates the influence of the transition substrate thickness on the fluctuation of the detector's operating temperature(Fig.5,Tab.3).In contrast to commonly used wires like gold wire,silicon-aluminum wire,and platinum wire,this study introduces the use of platinum-iridium wire with high strength and low thermal conductivity in aerospace-grade packaging design for the first time(Fig.8).The components were evaluated for aerospace mechanics. Results and Discussions Among the various components of the Dewar,the radiation from the Dewar window has a significant impact on the stray light of the 2 k×2 k detector.The stray light emitted by the 300 K Dewar window accounts for approximately 29.9%of the detector signal illumination(Fig.2).However,by implementing a low-temperature optical design with a 200 K Dewar window,the stray light emitted by the window is reduced to only 5.9%of the detector signal illumination.To minimize window deformation,the window cap is appropriately thickened.Fortunately,the impact of window cap deformation on the imaging quality of the optical system can be disregarded under all three working conditions(Tab.2-3).In order to mitigate the noise caused by mechanical disturbances from the refrigerator,a 5 cm thick layer of SiC substrate is added between the detector and the cold head.This effectively eliminates noticeable noise disturbances in the central area of the detector(Fig.5),resulting in a detector operating temperature fluctuation of less than 0.1 K(Tab.4).Furthermore,the use of platinum-iridium wire as component bonding wire improves both the conduction heat leakage and lead strength of the Dewar.The maximum conduction heat leakage is reduced from 576 mW to 49 mW,leading to a corresponding decrease in refrigerator power consumption from 72 W to 39 W.Additionally,the lead pull force experiment shows a value greater than 0.245 N,indicating satisfactory lead strength.The encapsulated components have successfully passed aerospace-grade mechanical tests(Fig.9). Conclusions This article aims to address challenges in the packaging technology of large-area array 2 k×2 k infrared detector components.The study focuses on various aspects including the low-deformation window support structure,low-noise cold platform structure,low heat leakage,and high-reliability wire bonding process.The research successfully resolves issues related to stray light,deformation of large-diameter windows,and detection in large area array detector packaging.By tackling problems such as detector noise,lead heat leakage,and strength,the study achieves an outstanding performance in the assembly of a large area array 2 k×2 k infrared detector.

红外透镜组的中心偏差是影响光学系统成像质量的重要因素之一.当红外探测器组件在低温环境中工作时,预先常温装配和测试的红外透镜组将产生装配精度失准现象.提出了 一种在低温环境中测试红外透镜组中心偏差的方法.通过设计的低温测试系统解决了透镜组低温位置精度测量困难的问题.测试结果表明,该方法可以有效实现红外透镜组中心偏差的低温测试且测试误差优于2μm.此研究对于高性能红外探测器组件研制具有一定的实际意义.

红外器件的封装中常需用一些透明材料制成零部件,适合采用脉冲激光对其进行切割和标刻加工,但需要对加工参数进行精细优化.文中以在用于红外焦平面封装的红外级康宁玻璃基片上进行激光标刻为例,对透明样品进行激光标刻所涉及的一些基本参数,包括烧蚀阈值、激光加工头的光束特性参数以及扫描偏角引起的几何误差等,进行了实际测量和分析,在此基础上得出了合适的打标策略和激光参数,并成功应用于实际操作.此种策略和参数设置方法可以推广到对其他透明材料进行激光标刻.

为了解决空间红外相机的高分辨率、高成品率及可维修性等问题,提出了先将6个线列探测器子模块拼接在一个“Z”字型的子基板上,再将多个(N≥5)这样的“Z”字型子基板通过精密拼接的方法以形成空间超长线列红外焦平面探测器.基于由多个子基板拼接形成的超长冷平台与单点冷源耦合以实现热交换的特点,针对超长冷平台温度均匀性小于1K及其与单点冷源间温度梯度小于5K的要求,建立了冷量传输通道的热网络模型,分析了影响冷量传输效率的主要因素,提出了优化各部件及不同部件螺接的接触热阻的方法,设计了两个“树状”柔性冷链实现了冷量向多基板冷平台高效传输.通过对加载不同总焦耳热时超长冷平台的温度均匀性及其与单点冷源间的温度梯度等热特性进行仿真和实验验证,结果表明超长冷平台温度均匀性误差小于0.05 K,温度梯度误差小于0.55 K,验证了由多个子基板拼接而成的超长冷平台与单点冷源间冷量传输模型合理可行,对于后续多基板精密拼接的工程应用提供重要参考.

在用于封装长波QWIP-LED量子阱探测器的杜瓦研制中,详细阐明了一种用于封装长波QWIP-LED量子阱红外探测器的结构,结构采用侧罩式设计,光信号从红外窗口进入,近红外窗口透出,提出了一种探测器胶接在管座上,管座整体再螺接在冷头的方法,提高探测器的互换性,通过热适配设计,降低低温应力对探测器影响,选择低冷损的TC4材料,降低杜瓦漏热,基本解决了长波QWIP-LED量子阱探测器杜瓦组件的关键技术,性能指标达标,成像效果良好,达到工程封装要求.

铂金丝作为低温器件封装中理想的键合丝,其键合质量的优劣决定着整个器件的性能和可靠性.通过25 μm的铂金丝球形键合试验,并使用OLYMPUS SMT-6三轴测量显微镜观察键合点形貌并测量第一键合点根部直径.结果 表明,当超声功率介于0.96～1.2 W时,增加超声功率有助于提高键合强度,增加工艺稳定性.在文中所设实验条件下,为保证键合强度和工艺稳定性,超声功率设置为1.2～1.28 W时最佳.第一焊点键合球平均直径为2.8WD(WD表示键合线直径)时,键合强度最大,工艺稳定性最好.总结出了键合点直径与拉力值关系图,从而通过键合点直径来评价键合质量.

针对超长线列红外探测器杜瓦具有容积大、零部件种类多、材料放气源多,特别是集成式超长线列杜瓦与内充3 MPa高压氦气的直线脉管冷指封装集成等特点,基于材料解析放气及渗透理论,建立了超长线列杜瓦组件真空寿命评估模型,对分置式与集成式超长线列杜瓦的真空寿命进行了计算,其真空寿命预计值均可以达到2年.设计了一种杜瓦真空度在线监测结构对这两类杜瓦的真空度进行了实时监测,分置式及集成式杜瓦真空寿命预计值与实测值相对误差分别为5.8％和6.96％.因集成式杜瓦真空寿命估算较为困难,对其热负载通过制冷性能进行实验验证,其热负载2年后未发生明显变化.

In most long linear infrared focal plane (IRFPA) Dewars, the detectors are supported by a bridge structure. Flexible thermal links are used to maintain uniform temperature of the cold platform. It is difficult to calculate the radiant heat of Dewar components using an empirical formula. In this study, the radiant heat of a Dewar is simulated using the ANSYS finite element method. Furthermore, the temperature field of the Dewar components is experimentally measured. The heat flow is calculated based on the thermal conductivity and temperature gradient. Consequently, the radiant heat is calculated indirectly. The results show that the deviation between the radiant heats simulated using ANSYS and calculated indirectly using the temperature field is approximately 2%.

The cold shield is an important part of the infrared detector assembly,and it will be cooled with the detector.Aiming at F2 cold shield for the 320 ×256,30 μm scale infrared detector,through cooling experiment with different technical conditions of cold shield in the same cold platform,the influence of the corresponding technical conditions of cold shield on the cooling process was studied,and the corresponding results were obtained under different technical conditions of cold shield.The results provide a reference for optimizing the thermal design of cold shield.

针对微型红外探测器组件的应用特点,介绍了国内外微型红外探测器组件集成技术的发展现状,重点阐述了红外探测器组件集成中的几种关键技术.这些技术的研究和发展对于推进微型红外探测器组件的应用至关重要.

Aiming at the requirement of fast cooling,low power consumption and environmental adaptability of 15μm 320 * 256 very long wavelength QWIP,the characteristics of low temperature integrated assembly of the 15μm QWIP were analyzed.Basedh on the cryogenic integration technology of coldfinger design,thermal design of the cold shield and cold platform auxiliary support structure design,so as,to achieve rapid cooling,low power consumption and high environmental adaptability of QWIP integrated assembly.After testing,the QWIP packaged with IDCA meets the requirements of the project.

大面阵红外探测器是红外遥感仪器的核心元件.该类探测器大多由小规模面阵探测器拼接组成,与杜瓦低温冷平台集成后形成杜瓦组件.探测器在杜瓦低温冷平台上安装集成后的应力状态是影响芯片性能和寿命的关键因素.测试了低温时探测器在自由状态下和被安装在杜瓦组件内应变片的热输出,再利用两者的差值表征了探测器与杜瓦低温冷平台集成后的额外应变.以2000×512探测器组件为例,进行了测试验证分析,结果表明该方法可行.

Highly hermetical laser sealing is a packaging technology which can be used for metal packages.It can achieve the sealing of a small hole of the metal package containing an infrared detector in a high vacuum environment.Thus,both the exhaust process and the sealing process of the infrared detector assembly can be finished at the same time.According to the structure and material of a micro package,the relation of the current and pulse width of a laser welding equipment to welding energy and the influence of the current,pulse width and defocusing distance on welding quality are analyzed.Proper laser welding parameters are obtained for Kovar materials.With those parameters,the laser sealing of a hole of the metal package containing an infrared detector is achieved.The test result shows that its leak rate is better than 1×10~(_10)Torr·1/s.