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  • Back-illuminated CMOS sensor performance and IPC product development

        Current digital technology, semiconductor manufacturing technology as well as a network of high-speed development of digital products in the market at an alarming rate, growth in key parts of the image sensor (Sensor) consisting of video, audio and visual products on current and future industry focus objects. The main image sensor both CCD and CMOS chips in our current high-definition field of security monitoring, two-chip technology is applied.
        The development and application of image sensor
        The eyes are the visual image sources, while the image sensor device is the image of the video capture device accepts. The image sensor according to the morphological classification are generally two types: linear image sensor, face image sensor. Linear image sensor used in scanners, copiers, fax machines and other equipment. Face image sensor is a wide range of applications in the security surveillance camera, cell phone camera, car reversing video camera, tablet computers and other well-known products.

        Just as we speak of a CCD image sensor and a CMOS chip two. Early, we usually think equipment with excellent image quality CCD sensor, and low-cost products use a CMOS sensor. But the new CMOS chip technology has overcome the weakness of the early CMOS sensor technology, compared to the old products to enhance the performance of low according to the design of the sensor, such as exposure mode. Take the popular back-illuminated CMOS sensor, in the conventional CMOS image sensor, the light-sensitive diode is located in the rear of the circuit transistor, the light through the circuit between the micro-lens and the photodiode and the transistor, then the amount of light will be due to obstructions affected.
        Back-illuminated CMOS sensor on the internal structure of the original image sensor optimized, it photosensitive layer of the original reverses direction, so that the light from the back directly into the chip to increase the amount of light, so the back-illuminated CMOS image sensor than conventional CMOS qualitative leap sensor light sensitivity in low light conditions, using a back-illuminated CMOS sensor HD camera with a great ability to focus, the image quality performance, image noise control performance boost.
        3,000,000 pixels latest HD IP camera and 1080P HD array infrared high-speed ball back-illuminated CMOS sensor, back-illuminated CMOS low according to performance with integrated LED Array device, compared to traditional CMOS products, due to good sense of back-illuminated CMOS sensor performance and the performance of infrared Sensor QE, significantly enhance the effect of cameras in low illumination and infrared fill light at night.
        In addition to the excellent low according to other properties, back-illuminated CMOS image sensor also has better high-sensitivity noise control performance. In other words, after the ISO improve, the noise than CCD much less. Image capture in low according to the environment has a great advantage, high frame rate performance is better. Are often high-speed back-illuminated CMOS sensor chip, many chip support full HD quality image output frame rate of 60 frames per second or higher, while the CCD sensor is more difficult in this regard.
        Now, most of the mainstream back-illuminated CMOS sensor HD camera support 1080P @ 30fps full HD video or 720P _AT_ 60fps. Our common CCD sensor monitor camera can only 720p _AT_ 25fps support 1080P format CCD sensor is too costly. Back-illuminated CMOS sensor pixels can be higher.
        Although both back-illuminated CMOS or CCD, can improve the effective pixels. But the structure of the back-illuminated CMOS sensor area of ​​the same case, you can further enhance the effective pixels, the picture quality is also better able to maintain. In contrast CCD to blindly raise pixels, the picture quality will be poor, and costs rising geometrically as pixels to improve the chip size is also larger.
        CCD sensor manufacturing process is more complex, CCD sensor camera prices are relatively high. In fact, through technological innovation, CCD and CMOS actual effect of the gap has been reduced a lot. And the manufacturing cost and power consumption of the CMOS chip to be much lower than the CCD, CMOS image sensor so many high-definition camera manufacturers. Imaging: the permeability of the same pixel CCD imaging Ming sharpness are very good color reproduction, exposure can be guaranteed to be basically accurate. The CMOS products screen permeability restore the weak capacity of the kind of color, exposure mode mostly Rolling Shutter mode capture distortion caused by high-speed moving objects sensor CMOS imaging quality CCD sensor in painting quality requirements more stringent scene or a certain distance. However, due to low prices, as well as a high degree of integration, the increasingly rapid development of high-definition camcorder market or get a wide range of applications.
        The image sensor of the latest R & D results
        2012 CMOS image sensors favored by the market because much lower than in the past CCD sensitivity problems due to the use of a new sensor technology, such as the back-illuminated CMOS gradually solved. Compared and a CCD sensor, CMOS sensor has a better mass productivity, and easy to implement other logic circuits, including SoC (System on Chip) products, which is difficult to achieve in the CCD chip. Unlike CCD, CMOS sensor chip as to require special manufacturing process, so you can directly use the equipment for the production of DRAM and other high-volume products. As a result, the CMOS image sensor, it is possible to form completely different from the cost structure of the CCD image sensor, as well as highly integrated CMOS sensor opens a new direction of development. Early market once launched CMOS sensor comes ISP processor, containing 2A (AE, AWB) control algorithm.
        Development so far, this product is a very welcomed by the market and favor. Many small businesses do not have the the ISP image processor / ISP algorithm research and development capabilities comes 2A processing CMOS sensor to produce a high-definition camera. Traditional HD camcorder architecture, the front end to the back-end is generally divided into several components: an image sensor SENSOR the ISP image sensor, compression / signal conversion process; integrated ISP´s CMOS sensor, the middle part of using the FPGA chip ISP unit can be omitted, so that not only effectively reduce the equipment overall BOM cost, and bypassing the the ISP algorithm developed threshold. The current market price is relatively cheap 720P HD IP video camera most of the use of such programs.
        Recently have manufacturers launched Integrated Real frame wide dynamic wide dynamic HD back-illuminated CMOS sensor, CMOS SENSOR function before integration 2A, frame wide dynamic sensor manufacturers adept use of this product. We know, for HD surveillance camera image processing, especially ISP relies in part on more than R & D capabilities, but also rely on the experience accumulated for image processing debugging. Own frame wide dynamic function a back-illuminated CMOS sensor products, not only the dynamic range of the sensor upgrade to more than 120dB saving R & D investment, and also for the video surveillance camera manufacturers.
        In addition to these integrated ISP image processing of the image sensor, the future market the integrated compression processing of the image sensor is one of the directions. The highly integrated core components of the camera is the development trend of the future, which have benefited from the CMOS sensor has better production, and easy to implement the architectural features of the other logic circuits.