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Canon image sensors
Mark Peters : October 12th 2005 - 15:36 CET
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 Canon image sensors : Electronic devices are designed using semiconductor process technology, device technology and mounting technology, then manufactured using semiconductor manufacturing technology. Canon has worked on the development of all these technologies for many years and is devoted to inhouse development and production to manufacture high-grade advanced devices. For example, the CMOS sensor incorporated in the EOS-1Ds Mark II D-SLR camera is a 35mm full-frame sized large sensor boasting 16.7 million effective pixels manufactured in-house. In addition to imaging sensors such as these CMOS sensors, Canon also develops and mass-produces a variety of electronic devices optimized for the characteristics of various products.
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 Canon - Optical imaging sensors
Canon develops imaging sensors such as CMOS sensors for SLR cameras and multi-chip contact sensors for scanners. Our current CMOS image sensor lineup ranges from APS-C size (approx. 22 mm x 17 mm) to 35 mm full-frame size (36 mm x 24 mm) sensors with 16.7 million pixels which offers an area over 34 times the size of sensors for compact cameras. When manufacturing these sensors, semiconductor process technology suited to the performance and size of each type is applied.
Full frame CMOS sensors - Batch production
In particular, sensors larger than APS-H size (28.7 mm x 19.1 mm) are beyond the size of the exposure area on which steppers can perform microscopic processing, making batch production difficult. As a result, these sensors are manufactured using segmented exposure, which requires advanced technology and production control.
CMOS - Noise cancellation circuit
The most important aspect of CMOS sensor performance is sensitivity (signal-to-noise ratio), to which Canon's own noise removal technology is applied. Each pixel in a CMOS sensor generally uses a 3-transistor structure made up of a photo diode, a pixel amplifier and a reset switch for initializing optical charge. Canon's sensors use a 4-transistor structure, which adds a transfer switch. A double sampling noise cancellation method was developed by using the transfer switch to preload different values of random noise for each operation, enabling accurate calculation and cancellation. The effect of this is realized in the achievement of ISO sensitivity of more than 1,600. Canon's CMOS sensor was awarded the National Commendation for Invention thanks to the noise cancellation circuit.
CMOS image sensor - Long exposures
CMOS sensors guarantee superior image quality even with long exposure times. Because imaging sensors accumulate optical signals as electric charges in order to form images, long exposure times tend to lead to "dark current" that results in the production of noise. Canon has investigated the cause of dark current and taken steps against it to create a CMOS sensor with very little dark current. This feature is made possible by in-house production in a specialized factory with strict production management.
Canon CMOS sensor - Optical detection sensors
Detection sensors for cameras include AF sensors, AE sensors, EF lens encoders and flash adjustment sensors. Detection sensors for business machines include laser beam detectors, paper type detection sensors and register mark detection sensors. These sensors utilize CMOS sensor technology for detecting, the amount and position of light. For example, in paper type detection sensors, processing software determines the type of paper by using differences in reflective patterns depending on the qualities of the paper.
Canon technology - Analog LSIs
These include CMOS sensor chipsets for SLR cameras, analog LSIs (VIF/VRP) for video and LBP drivers. Camera chipsets are made up of chips performing analog preprocessing and digital preprocessing of data from the CMOS sensor before it is sent to the imaging engine, and timing generators for controlling each chip. These are tuned to ensure maximum performance of CMOS sensors.
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