Abstract: A focusing method and apparatus, for use with digital cameras having an electronic viewfinder with less display resolution than in the image generated by the camera's photocell array, uses a uniformly subsampled representation of the entire image for focusing, rather than displaying a selected portion of the higher resolution image. The focusing is assisted by the exaggerated discontinuities produced by subsampling. Introducing flicker enhances focusing sensitivity by repetitively displaying, on the electronic viewfinder, a prescribed set of different reduced-resolution images obtained by subsampling the same high-resolution image at different sampling locations. Each subsampled image of the set of reduced resolution images uses a different set of substantially uniformly distributed pixels.

Abstract: A storage pixel sensor comprises a photosensor selectively connectable to a reset potential; a switched buffer amplifier having a control terminal coupled to said photosensor, a first terminal connected to a source of a transfer signal, and a second terminal; a storage capacitor coupled to said second terminal of said switched buffer amplifier; and an amplifier coupled to said storage capacitor.

Abstract: A vertical color filter detector group according to the present invention is formed on a semiconductor substrate and comprises at least six layers of alternating p-type and n-typed doped regions. PN junctions between the layers operate as photodiodes with spectral sensitivities that depend on the absorption depth versus wavelength of light in the semiconductor. Alternate layers, preferably the n-type layers, are detector layers to collect photo-generated carriers, while the intervening layers, preferably p-type, are reference layers and are connected in common to a reference potential referred to as ground. Each detector group includes a blue-sensitive detector layer at an n-type layer at the surface of the semiconductor, a green-sensitive detector layer at an n-type layer deeper in the semiconductor, and a red-sensitive detector layer at the n-type layer deepest in the semiconductor.

Abstract: A method for attaching imagers to color-separation prisms includes the steps of: arranging three solid-state array image sensor integrated circuits behind and in close proximity to the output faces of a color-separating prism having substantially equal optical path lengths for the three paths, the three solid-state array image sensor integrated circuits each having a solid-state array image sensor and bonding pads for electrical connections disposed on a top face thereof; aligning the three sensors such that the images traversing the three paths are coincident within a pixel dimension of the image sensors; filling the space between each output face of the prism and the top face of the corresponding image sensor with index-matched adhesive; and causing the index-matched adhesive to become rigid while maintaining the alignment of the three image sensors.

Abstract: An active pixel sensor is disposed on a semiconductor substrate of a first conductivity type, and comprises a plurality of semiconductor regions disposed in the substrate, each successive one of the semiconductor regions being enclosed entirely within another enclosing one of the semiconductor regions. The plurality of semiconductor regions alternates between the first conductivity type and a second conductivity type opposite to that of the first conductivity type. A first enclosing one of the semiconductor regions containing all other ones of the semiconductor regions is of the second conductivity type, such that a plurality of series-connected photodiodes is formed between the substrate and an innermost enclosed one of the semiconductor regions. A plurality of reset switches each has a first terminal coupled to a different one of the alternating semiconductor regions, and a second terminal switchably coupled to a reset potential.

Abstract: A vertical color filter detector group according to the present invention is formed on a semiconductor substrate and comprises at least six layers of alternating p-type and n-typed doped regions. PN junctions between the layers operate as photodiodes with spectral sensitivities that depend on the absorption depth versus wavelength of light in the semiconductor. Alternate layers, preferably the n-type layers, are detector layers to collect photo-generated carriers, while the intervening layers, preferably p-type, are reference layers and are connected in common to a reference potential referred to as ground. Each detector group includes a blue-sensitive detector layer at an n-type layer at the surface of the semiconductor, a green-sensitive detector layer at an n-type layer deeper in the semiconductor, and a red-sensitive detector layer at the n-type layer deepest in the semiconductor.

Abstract: A digital pixel sensor is formed on a semiconductor substrate and comprises a phototransducer responsive to light for providing an analog output signal that is a function of an incident amount of light. A comparator is configured to compare the analog output signal and a ramp reference signal. A plurality of n DRAM cells are configured to store an at least n-bit digital signal in response to the output of the comparator. An array of digital pixel sensors is also disclosed.

Abstract: A scanning circuit for use with an active pixel sensor array comprises a row-address generator configured to start at a selected row-start address, stop at a selected row-stop address, and increment row addresses by a factor K. A column-address generator is configured to start at a selected column-start address, stop at a selected column stop address, and increment column addresses by a factor K. Circuitry is coupled to the row address generator and the column address generator, for storing the row-start address, the row-stop address, the column-start address, the column-stop address and the factor K. A row decoder is coupled to the row-address generator and a column selector is coupled to the column-address generator. A plurality of row select lines are coupled to the row decoder, each one of the row select lines associated with a different row in the active pixel sensor array.

Abstract: A storage pixel sensor disposed on a semiconductor substrate comprises a photosensor. At least one nonlinear capacitive element is coupled to the photosensor. At least one nonlinear capacitive element is arranged to have a compressive photocharge-to-voltage gain function. An amplifier has an input coupled to the nonlinear capacitor and an output. Other, non-capacitive elements may be employed to produce a compressive photo-charge-to-voltage gain having at least one breakpoint.

Abstract: A method for storing a full Red, Green, Blue (RGB) data set. A full RGB data set is three-color image data captured with an imager array formed on a semiconductor substrate and comprising a plurality of vertical-color-filter detector groups. Each of the vertical color detector groups comprises three detector layers each configured to collect photo-generated carriers of a first polarity, separated by intervening reference layers configured to collect and conduct away photo-generated carriers of opposite polarity, the three detector layers being disposed substantially in vertical alignment with respect to one another and having different spectral sensitivities. The three-color image data is then stored as digital data in a digital storage device without performing interpolation on the three-color image data.

Abstract: An active pixel sensor including low threshold voltage transistors advantageously provides an increased output swing over an active pixel sensor of the prior art. The low threshold voltage transistor can be achieved using either a native transistor or a depletion mode transistor. In a process in which a threshold adjustment implant step is separately masked, the active pixel sensor of the present invention can be manufactured with no additional masking requirements. In one embodiment, a low threshold voltage (VTN) allows a transistor acting as a reset switch to operate in the linear region, and allowing the reset switch transistor to share a common supply voltage source with a readout amplifier transistor.

Abstract: A method for controlling the exposure of an active pixel array electronic still camera includes the steps of: integrating photocurrent in each pixel during an integration time period; collecting overflow charge from all pixels in the array during the integration time period; developing an overflow signal as a function of the overflow charge; and terminating the integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level.

Abstract: An integrated active pixel sensor array comprises a plurality of row select lines, each of said row select lines coupled to a source of a row-select signal; a plurality of source-follower drain row lines, each of said source-follower drain row lines coupled to a source of a source-follower drain row signal; a plurality of column output lines; a reset line coupled to a source of a reset signal; a source of reset potential; and a plurality of active pixel sensors, each pixel sensor associated with one row and one column of the array and including a photodiode having a first terminal coupled to a first reference potential and a second terminal, a Reset transistor having a gate coupled to the reset line, a drain coupled to the reset potential to reverse bias the photodiode, and a source coupled to the second terminal of the photodiode, a Source-Follower transistor having a gate coupled to the second terminal of the photodiode, a drain connected to the one of the plurality of source-follower drain row lines with w

Abstract: A vertical color filter detector group according to the present invention is formed on a semiconductor substrate and comprises at least six layers of alternating p-type and n-typed doped regions. PN junctions between the layers operate as photodiodes with spectral sensitivities that depend on the absorption depth versus wavelength of light in the semiconductor. Alternate layers, preferably the n-type layers, are detector layers to collect photo-generated carriers, while the intervening layers, preferably p-type, are reference layers and are connected in common to a reference potential referred to as ground. Each detector group includes a blue-sensitive detector layer at an n-type layer at the surface of the semiconductor, a green-sensitive detector layer at an n-type layer deeper in the semiconductor, and a red-sensitive detector layer at the n-type layer deepest in the semiconductor.

Abstract: A storage pixel sensor disposed on a semiconductor substrate comprises a capacitive storage element having a first terminal connected to a fixed potential and a second terminal. A photodiode has an anode connected to a first potential and a cathode. A semiconductor reset switch has a first terminal connected to the cathode and a second terminal connected to a reset potential. A semiconductor transfer switch has a first terminal connected to the cathode and a second terminal connected to the second terminal of the capacitive storage element. A semiconductor amplifier has an input connected to the capacitive storage element and an output. The semiconductor reset switch and the semiconductor transfer switch each have a control element connected to a control circuit for selectively activating the semiconductor reset switch and the semiconductor transfer switch.

Abstract: A method for controlling the exposure of an active pixel array electronic still camera includes the steps of: integrating photocurrent in each pixel during an integration time period; collecting overflow charge from all pixels in the array during the integration time period; developing an overflow signal as a function of the overflow charge; and terminating the integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level.

Abstract: A color-separation prism assembly comprises first, second and third prisms. The first and second prisms have entrance surfaces, exit surfaces, and partially-reflecting surfaces, wherein the entrance surface of the second prism is separated by an air gap from the partially-reflecting surface of the first prism. The third prism has an entrance surface and an exit surface, wherein the entrance surface of the third prism is adjacent to the partially-reflecting surface of the second prism. The first prism has a cut-out serving as a flare-stop stop, and providing relief so as to allow the entrance surface of the third prism to slide across a plane disposed over the cut-out into a volume defined by the cut-out. The plane is formed as an extension of the partially-reflecting surface of the first prism. An optical axis passes through the first, second and third prisms. The optical axis passes at normal angles through the entrance surface of the first prism, and the exit surfaces of the first, second and third prisms.

Abstract: An active pixel sensor is operated with voltages that exceed the nominal operating voltages for a particular integrated circuit process. Voltages that exceed the nominal operating voltages are employed during the reset, integration and readout periods in the operating cycle of the active pixel sensor. The lower limit of the voltage representing the capture of photocharge in the active pixel sensor is fixed by setting the voltage applied to the gate of a reset transistor in the active pixel sensor to a level during integration which prevents the voltage across the dielectric of a transfer transistor from exceeding a preselected value. Read disturb caused by impact ionization current from a readout transistor to a storage node is reduced by lowering the voltage applied to the drain of a readout transistor to reduce the Vds of the readout transistor at the start of a readout period.

Abstract: An active pixel sensor including low threshold voltage transistors advantageously provides an increased output swing over an active pixel sensor of the prior art. The low threshold voltage transistor can be achieved using either a native transistor or a depletion mode transistor. In a process in which a threshold adjustment implant step is separately masked, the active pixel sensor of the present invention can be manufactured with no additional masking requirements. In one embodiment, a low threshold voltage (VTN) allows a transistor acting as a reset switch to operate in the linear region, and allowing the reset switch transistor to share a common supply voltage source with a readout amplifier transistor.

Abstract: In a first embodiment an active pixel sensor includes a photodiode for capturing photocharge, a reset transistor for resetting the photodiode to a reset potential, and a readout transistor, and in a second embodiment an active pixel sensor includes a photodiode for capturing photocharge, a reset transistor for resetting the photodiode to a reset potential, a transfer transistor for transferring captured photocharge, and a readout transistor. In both embodiments, the readout transistor has a drain that is coupled to a first supply voltage during integration of photocharge and a second supply voltage during readout of the photocharge. Accordingly, the sensitivity of an active pixel sensor is increased by increasing the fill factor, the noise an active pixel sensor is reduced by increasing the relative size of the readout transistor, and the gain is compressive as the relative light intensity in an active pixel sensor increases.