CCD

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CCD

Abbrev. for charge-coupled device. A light-sensitive electronic detector, invented 1970, now widely used in ground- and space-based astronomy for imaging, photometry, spectroscopy, astrometry, etc. CCDs are normally sensitive over a wide range of wavelengths from blue light to near-infrared; developments have extended the range further into the IR (see infrared detectors), and into the ultraviolet and X-ray regions (to energies up to about 6 keV). A CCD is small (typically several square centimeters) compared with a photographic plate, and therefore covers a relatively small field of view. It also has a lower resolution than a fine-grained photographic emulsion. It does, however, have a much higher quantum efficiency – i.e. is a much more efficient detector – than emulsion; exposure times are therefore relatively much shorter. CCDs are thus well suited to the imaging of faint objects. They also have a linear response over a wide range of illumination, and in a properly designed and operating CCD system, the response is very stable over long timescales.

Astronomical CCDs are fabricated as a two-dimensional array of tiny pixels (picture elements) on a thin wafer of semiconductor, usually silicon; there may be up to several thousand rows and columns of pixels. When light or other radiation is directed onto this array, each pixel responds to the photons falling on it by producing electrons. Electric charge thus accumulates in each pixel in proportion to the amount of incident radiation. After an exposure, these packets of charge are shifted out of the array and the accumulated charge in each pixel is measured, row by row. The values are digitized and stored in a computer, and may be used to form an image on a computer screen or may be further manipulated or analyzed. There is a direct relationship between the intensity of the recorded image and the original exposure, hence the linear response. Noise is, however, introduced as the charges are moved out of the CCD, amplified, digitized, and stored in the computer, thus placing a lower limit on the signal that can be accurately recorded; this readout noise can be reduced by cooling the CCD.

CCD

(electronics)

CCD

CCD

(1) (Charge-Coupled Device) See CCD sensor.

(2) (Consumer Computing Device) An earlier term for a low-cost consumer-oriented computing product such as a PDA or Internet appliance.
References in periodicals archive ?
* What are the key market trends impacting the growth of the global CMOS image sensor market?
The specification of the proposed ADC is summarized with some other prior arts in CMOS image sensor field as shown in Table 1.
Through the further development of CMOS image sensors, Canon will break new ground in the world of image expression, targeting new still images that largely surpass those made possible with film, and video movies that capitalize on the unique merits of SLR cameras, namely their high mobility and the expressive power offered through interchangeable lenses.
"There is a growing demand for CMOS image sensor modules with better image quality," said Joseph Li, chief executive, in a press release.
The camera is a 310,000-pixel CMOS image sensor with adjustable white balance (on a PDA!) and has a 2-times digital zoom.
recently announced its prototype SD9 SLR digital camera, which utilizes Foveon's CMOS image sensor X3, featuring decreased power consumption and ease of manufacture by using standard LSI chip making lines.
The industry has been grappling with the problem of developing a high quality CMOS image sensor for 20 years.
Together, ON Semiconductor and 3M combine decades of image sensing technology and roadway safety experience, to help improve navigation for vehicles equipped with automated driving features.During CES 2019 in Las Vegas, Nevada, the two companies will display ON Semiconductor's AR0234AT CMOS image sensor integrated with 3M's next generation digitally-enabled Smart Code sign technology in the ON Semiconductor demo room at the Venetian, Level 3, Murano 3302 & 3303.
ON Semiconductor is now offering a fully AEC-Q100 qualified version of its popular 2.1 MP CMOS image sensor, AR0237 for the burgeoning OEM-fitted dash cam or before-market in-car DVR market.
Leveraging its own background in CMOS scaling as well as its semiconductor fab, equipment, and process technology, imec also designs and manufactures interference-based optical filters at wafer level, deposited and patterned directly on top of the CMOS image sensor pixels.
With an OPF CMOS image sensor, the charge-storage function and photoelectric-conversion function can be set independently.