Fairchild Camera and Instrument Corp.

Loral Fairchild Corporation

Other

Sangamo Weston, Inc.

Lockhead Martin Corp.

Fairchild Imaging, Inc.

Rudolph H Dyck

James M Early

Jae S Kim

Inderjit K Aulakh

Michael E Dyck

A CCD image sensor with a color filter array (CFA) for color imaging involves stripes of Cyan and of Yellow filter material on the imaging surface of a CCD array, preferably a full-frame (FF) CCD imager, with the two sets of color stripes arranged perpendicular to each other and one set parallel to the array axes to form two layers at the areas where they cross. Unit color cells comprise 2-pixel by 2-pixel blocks, each containing a Cyan, a Yellow, a Green (where the stripes overlap), and a White (where there is no stripe) pixel. Also, the longitudinal set can be segmented into two pixels or more in length, and the segments transversely displaced or staggered to form an elongated checkerboard pattern to compensate for devices with single-column blemishes. In fabrication, the filter stripes of one color are deposited crossing over the others to form two layers with different thicknesses so that the later deposited stripe has spectral properties in the cross-over regions distinctly different from non-cross-over regions, permitting the production of a four-color image CCD sensor chip with fewer fabrication steps and improved yield. The resulting chip has the sensed image charge read out after only one exposure to generate the desired color image data file, and a 2&times;2 pixel block of a unit cell can be virtually shifted by one pixel both longitudinally and transversely so that complementary 2&times;2 pixel blocks can also be used to generate unique color image data. Another arrangement using Cyan and Yellow filter material in the form of circular discs or octagons is also disclosed.

Image sensor with stripes of cyan filter material perpendicular to stripes of yellow filter material

A multiple-frame image sensor comprising a full-frame CCD sensor of two-story construction having an overlying photosensitive layer that converts input radiation to electric charge and an underlying CCD structure which functions to collect and store the charge for read-out of more than one charge packet per pixel, with the pixels being of minimum size. The sensor structure is rendered capable of handling more than one photosignal charge packet per pixel in an area-efficient way through the use of ripple clocking, so that in a preferred embodiment a 4-poly, 7-phase ripple-clocked vertical CCD register is fabricated with 7 gates, one of which is run vertically to create openings, e.g., between the 1 and 6 gates, that pass electrode contacts to N+ sources in the channel stops of the register to form photosignal charge packets in the region between the stops. The ripple-gating controls the movement of the charge packets for storage along the CCD channel until 3 charge packet read-out. In this two-story embodiment, there is no mixing of signal charge from the several exposures. Other embodiments involving 3- and 2-poly designs, MPP barriers, and 5-phase ripple-clocking and 6-electrode non-ripple clocking are described.

Multiple-frame CCD image sensor with overlying photosensitive layer

A CCD sensor structure adapted for backside illumination, has a wide depletion layer separating the illuminated surface from potential barrier-like structures, e.g., in the form of a series of p-wells, that shield portions of the CCD channels and that cause the photoelectrons to converge through 'ports' between the p-wells into selected regions of the CCD channels. The potential barriers are thus arrayed to delineate at the CCD surface a series of charge-packet-forming or integrating regions, each of which has two (or more) adjacent shielded charge-packet-holding or storage regions into which the frame-indicative charge packets are successively shifted upon receipt of the light from successive image frames. With an anti-reflective coating on the illuminated back surface, this device not only provides 100% fill-factor for each of the successive frames, but also can provide very high quantum efficiency (QE) across the visible spectrum. A preferred embodiment utilizes 7-phase (non-barrier-type) ripple clocking for charge packet readout.

Rapid-sequence full-frame CCD sensor

Apparatus and method of filling tubes of flexible, large mesh, netting material with compacted rice straw, or the like. The finished straw tubes are on the order of nine inches in diameter, twenty five feet in length and thirty pounds in weight; and thus readily lend themselves to use in controlling or mitigating the effects of erosion and to promoting revegetation.

Machine for producing straw-filled tubes of flexible netting material

The disclosure describes one unit cell of a PNPN photoswitch array for an image sensor, including a PNPN light-activated thyristor (LAT), in the form of a two-terminal device, and a load FET. The FET functions as a load and as an on-off switch in series. The output of is a voltage at a first n node that controls the FET switch that connect a voltage-ramp input line to a capacitor and a diode that are connected in parallel. The other side of the diode is the input source of the unit cell that feeds charge into a vertical CCD analog shift register. At the start of a cycle of operation, such as the beginning of a sweep of a radiation beam and prior to a pulse of a target reflection pulse, being directed onto the pnpn photoswitch, the voltage level at the first node is high. At the time when a pulse of radiation is directed onto the photoswitch the first node goes low turning the switching transistor off. The capacitor has a charge level at an analog value representative of the elapsed time between the beginning of the cycle, such as the beginning of a radiation beam sweep, an the occurrence of the pulse reflected from a target. At the end of a cycle the charge is transferred into a CCD readout register.

Switching photosensitive matrix device

A self-aligned element antiblooming structure for application to charge-coupled devices includes a region in the substrate in which the charge-coupled device is fabricated into which both a P and an N conductivity type impurity are introduced. By introducing impurities of different diffusivities, a sink region is created between two very narrow antiblooming barriers. Using appropriate process controls, the potential height of the antiblooming barriers may be adjusted to drain excess charge accmulating in the substrate adjacent the antiblooming barriers. In this manner the antiblooming function is accomplished using only a minimal area of the substrate. The invention is applicable to charge-coupled devices utilizing a variety of different clocking schemes, and to charge-coupled device image sensors using buried channels.

Self-aligned antiblooming structure for charge-coupled devices and

A line scan image sensor capable of operating at several different spatial sampling frequencies is provided by utilizing a line scanning array having sampling photoelements of different surface areas. The spatial sampling frequency of the sensor can be varied by selectively combining the charge packets generated by the individual photoelements. In a preferred embodiment, photoelements having two different surface areas are used, with the ratio of the smaller surface area with respect to the larger surface area being 1:.sqroot.2. A programmable amplifier is provided to normalize the outputs of photoelements having different surface areas so that a uniform illumination on different photoelements will produce a uniform response. The programmable amplifier can also be programmed to equalize the outputs of the sensor between the different spatial sampling frequency modes.

Selectable resolution line-scan image sensor

A sensor optimized for detecting infrared radiation is formed by a Schottky barrier photodiode having a corrugated upper surface upon which a thin layer of metal silicide is deposited. The corrugated surface is formed by selective etching of a (100) silicon wafer to expose the (111) crystalline plane.

Grooved Schottky barrier photodiode for infrared sensing

A programmable charge coupled device transversal filter 5 includes a charge coupled device register 10 for receiving and delaying incoming analog signals, a series of floating gate charge detectors 15, a corresponding number of sets of binary scaled capacitors C.sub.0, . . . 2C.sub.0 . . . 2.sup.n C.sub.0, an output circuit including a positive and negative bus coupled to a differential amplifier, and mask or otherwise definable electrical connections for connecting selected ones of the scaled sets of capacitors between the floating gate 15 corresponding to that set and one of the positive and negative buses 22 and 23.

Mask programmable charge coupled device transversal filter

A self-aligned element antiblooming structure for application to charge-coupled devices includes a region in the substrate in which the charge-coupled device is fabricated into which both a P and N conductivity type impurity are introduced. By introducing impurities of different diffusivities, a sink region is created between two very narrow antiblooming barriers. Using appropriate process controls, the potential height of the antiblooming barriers may be adjusted to drain excess charge accumulating in the substrate adjacent the antiblooming barriers. In this manner the antiblooming function is accomplished using only a minimal area of the substrate. The invention is applicable to charge-coupled devices utilizing a variety of different clocking schemes, and to charge-coupled device image sensors using buried channels.

Self-aligned antiblooming structure for charge-coupled devices

Apparatus for amplifying output signals from a charge coupled area imaging device includes a resettable first floating gate amplifier connected to sense charge in the charge coupled device output register at a first location, a second floating gate amplifier connected to sense charge in the charge coupled device output register at a second location, and a charge limiting well disposed between the first location and the second location to remove charge in excess of a desired amount before the output signals are sensed at the second location. The dual preamplifiers permit optimization of the output signals from the charge coupled imaging device for two substantially different light levels by providing a substantially lower noise equivalent input signal level from the second preamplifier.

Growing community of inventors

Palo Alto, CA, United States of America

Rudolph H Dyck