# Near-Space Wide-Area and High-Resolution Imaging System Design and Implementation
## 2 Wide-Area and High-Resolution System Design
### High-Resolution Camera Design
#### 2.1.5 Electrical and Mechanical Design  
The electronic system of a high-resolution camera consists of CMOS sensors, an image data processing interface, signal processor, power converters, control input, and image output interfaces. The composition of the camera system is shown in Figure 11.  
The development of the detector has gone through multiple stages, including scheme design, structural design, PCB design, prototype debugging, and overall testing. The PCB circuit stack installation structure of the detector is shown in Figure 12.  
To ensure the implementation of optical design, the mechanical structure of the camera mainly includes three parts: a front mirror component, a focusing mirror component, and a detector component, as shown in Figure 13.  
The front mirror component contains the five optical lenses of the camera. In order to meet the requirements for the co-axiality of the optical path, structural stability, and ease of assembly and adjustment, the assembly adopts an integral cylindrical structure. The front mirror component mainly includes the mirror tube, protective cover, pins, compression rings and washer fixing parts, spacers, mirror boxes, trimming pads, etc. The lens barrel mainly provides support and positioning for various optical lenses and is fixedly connected to the focusing lens component.  
Figure 10: Tolerance analysis results: (**a**) 106.7 mm; (**b**) 320 mm.  
The focusing mirror component includes the four optical lenses of this camera. Considering the optical design requirements and structural simplification, the component is designed as an I-type straight-through lens tube structure; this component is in the middle of the entire camera, and square flange plates are placed at both ends to connect the front mirror component and detector component. Since there is a lens in the optical system that is sensitive to changes in ambient temperature, a focusing module is placed in the focusing mirror assembly. The focusing module consists of a stepping motor, big and small gears, and photoelectric travel switches--and its corresponding structural parts. Through the design of the number of teeth, modulus, and pressure angle of the big and small gears, a reasonable reduction ratio is optimized. With the help of the electronic control system, the optical focusing requirements are met.  
The temperature environment during camera operation fluctuates greatly, and a higher temperature will affect the imaging quality of the CMOS sensor. To ensure that the CMOS sensor operates in an ideal temperature environment, thermal conductivity cooling is used to timely dissipate the heat generated by the CMOS sensor during operation. There is a thermal conductivity plate on its back, with one end fixed to the back of the CMOS chip  
Figure 11: Electrical composition of the camera.  
Figure 12: Electrical structure of the camera.  
Figure 13: Mechanical structure of the camera.  
and an insulation pad added at the fixed position. The other end is led out, and then heat is transmitted to the thermal control component to achieve conducting cooling. The thermal conductivity plate is made of red copper (T3) with high thermal conductivity. To improve the thermal conductivity efficiency and increase the contact area, a combination of mechanical pressing and thermal adhesive bonding is used to fix it. The CMOS base is made of titanium alloy material, which has a certain strength and low thermal conductivity, which is conducive to the thermal control of CMOS chips.