Digital camera circuit

Digital camera circuit. (Courtesy of Matsushita Electronics Corporation. DuPont Application... 

Graves and Willems [48] provide an example of a network model to determine safety stocks in a supply chain at Eastman Kodak. The supply chain involves a high-end digital camera in which the camera, procured from an outside vendor, came with lens, shutter, and focus functions. The imager, circuit board assembly, and many other parts were assembled and tested. The final product was then moved to a distribution center and shipped against demands. The parts in the camera were classified into two groups, one with a lead time of under 60 days and the other set with a lead time of over 60 days. 

The most commonly used image-capture device in a digital camera is an array of CCDs. The schematic of a small portion of such an array is shown in Fig. 5. Each individual device eiement, i.e., each pixel, comprises a potential well in the doped silicon substrate. It is linearly connected with other such elements in series. Photoelectrons created by exposure of the pixel, on a more or less one-for-one basis, are trapped in the well associated with that pixel, then shifted to the well of the next pixel in the series by sequential application of a voltage to the electrodes (A, B and C in Fig. 5) adjacent to the well. The electric fields associated with these voltages effectively create artificial potential wells under the electrodes. The packets of photoelectrons ultimately emerge sequentially into an external circuit, in the inverse order to the physical arrangement of the pixels relative to the external circuit connection (drain). 

This credit-card-sized digital camera (Figure 1.26) uses multilayer LTCC materials to reduce the size of the printed wiring board by 50%. The 10-layer circuit used fine-line silver conductors and integrated thick-film resistors having one half the volume of the equivalent chip resistor volume to achieve this significant reduction in size, as well as cost savings. 

FIGURE 61.3 Flexible circuits applied for digital camera. (Courtesy of Canon). 

Portable electronic products are exposed to more severe conditions than ever before. As a result, they need higher reliability for the circuits as listed in Table 61.3. In the case of portable telephones, they are often carried in the owner s pocket, where they may be exposed to a variety of conditions, including continuous vibration, mechanical shock, temperature, humidity, pocket Unt, and even perspiration. Other portable electronic products, such as digital cameras, PDAs, and notebook computers, could be exposed to similar conditions. 

ACA flip-chip technology has been employed in many applications where flip chips are bonded to rigid chip carriers [13]. This includes bare chip assembly of application-specific integrated circuits (ASICs) in transistor radios, personal digital assistants (PDAs), sensor chips in digital cameras, and memory chips in laptop computers. In all the applications, the common feature is that ACA flip-chip technology is used to assemble bare chips where the pitch is extremely fine, normally less than 120 pm. For those fine applications, it is apparent that the use of ACA flip chips, instead of soldering, is more cost-effective. 

Closed circuit TV (CCTV) cameras (color or black-and-white) for furnace systems are usually industrial surveillance types (typically 540-line high-resolution). These transmit the images of combustion to normal industrial-type monitors, which may be in a control room or locally at the viewing site. The process can also be digitally recorded for further evaluation. 

In a video microscope, the eyepiece and the eye are replaced by a CCD array such as that used in an ordinary closed-circuit television camera. The image may be viewed directly with a video monitor, or digitized and enhanced with Si frame digitizer. 

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