Charge-Coupled Information Storage
US 3,858,232Localized Charge Storage and Serial Transfer Through Semiconductor Potential Wells
How It Works: Step-by-Step Mechanical & Physical Breakdown
An electrode and insulating layer form a field-controlled depletion region in a single-conductivity semiconductor. The electric potential energy of a carrier varies with position; a local minimum is a storage well. The source's transfer condition is overlap: before the first well is removed, a next well is established so diffusion and the electric field carry the stored charge into it. It describes two- and three-phase drive variants, surface and buried channels, and detectors that convert the stored charge or its capacitance into an observable signal.
Interactive Real-Time Physical Simulation
Detailed Component Architecture
1MOS Depletion Potential Well Matrix
Positive bias creates surface depletion regions with deep potential wells (), confining up to photoelectrons per pixel with negligible spatial crosstalk.
23-Phase Polysilicon Shift Register
Overlapping gate geometry eliminates potential pockets and achieves a Charge Transfer Efficiency exceeding 99.999% (), preventing trailing charge smear across thousands of shift steps.
3Lateral Channel Stops
High acceptor doping () pins the surface potential near zero, preventing photo-generated charge packets from blooming or diffusing into adjacent column channels.
4Floating Diffusion Readout Node
Translates microscopic femtocoulomb charge packets into low-noise analog voltage steps (, sensitivity ) with correlated double sampling (CDS) reset.
Governing Equations & Colorized Principles
3-Phase MOS Potential Well Charge Transfer & Storage Capacity
Digital Imaging & Image SensorsClaim 1Pixel Full-Well Capacity
Incident photons generate electron-hole pairs via the photoelectric effect, accumulating photoelectrons in potential wells under positive gate electrodes.
Boyle and Smith invented the Charge-Coupled Device in under an hour during a Bell Labs brainstorming session on silicon memory. They created a semiconductor electronic eye where light is converted into charge packets and shifted out like water buckets in a bucket brigade.
Historical Context: US 3923554 eliminated photographic chemical film, enabling digital cameras, smartphones, astronomy (Hubble Space Telescope), and medical endoscopy.
Internal Photoelectric Effect & Charge Accumulation
computingPhotoelectron Packet Count
Governs photoelectron packet count within internal photoelectric effect & charge accumulation: Photons with energy exceeding the silicon bandgap () excite valence electrons into the conduction band, accumulating a stored charge packet () preci...
Photons with energy exceeding the silicon bandgap () excite valence electrons into the conduction band, accumulating a stored charge packet () precisely proportional to optical intensity.
MOS Surface Depletion Potential Well Depth
computingPsi (ψ) (_s)
Governs psi (ψ) (_s) within mos surface depletion potential well depth: Positive voltage applied to the gate electrode pushes away majority holes, creating a positive donor ion depletion layer with an electrostatic potential well () that traps ...
Positive voltage applied to the gate electrode pushes away majority holes, creating a positive donor ion depletion layer with an electrostatic potential well () that traps minority electrons.
Charge Transfer Inefficiency (CTI) & Image Contrast
computingOutput / Input Charge Signal Packet
Governs output within charge transfer inefficiency (cti) & image contrast: Even a tiny transfer inefficiency () causes significant image degradation over shifts. Boyle & Smith's three-phase geometry reduced $\epsilon < 10^{...
Even a tiny transfer inefficiency () causes significant image degradation over shifts. Boyle & Smith's three-phase geometry reduced , preserving sharp image contrast across megapixel arrays.
Floating Diffusion Charge-to-Voltage Sensitivity
computingFloating Diffusion Sense Output Voltage
Governs floating diffusion sense output voltage within floating diffusion charge-to-voltage sensitivity: Minimizing the capacitance of the floating output node () maximizes the output voltage conversion gain, allowing single-electron detection above thermal nois...
Minimizing the capacitance of the floating output node () maximizes the output voltage conversion gain, allowing single-electron detection above thermal noise.
Thermal Dark Current Generation
computingThermal Dark Current / Surface Recombination Velocity
Governs thermal dark current within thermal dark current generation: Thermal generation of electron-hole pairs in the depletion region and surface states creates spurious 'dark current.' Deep-space astronomical CCDs are cryogenically cooled to $-100...
Thermal generation of electron-hole pairs in the depletion region and surface states creates spurious 'dark current.' Deep-space astronomical CCDs are cryogenically cooled to to suppress .
Interactive Schematic Sheet (FIG. 1A)
FIG. 1A from the local US 3,858,232 facsimile: charge generation and the first potential well.
Select Any Numbered Pin
Click pins on the schematic or select from the list below to inspect historical specifications.
Why It Still Matters
Boyle and Smith's CCD sensor transformed human civilization: it enabled modern astronomy (including the Hubble and James Webb Space Telescopes), digital photography, video camcorders, endoscopy and medical imaging, barcode scanners, and the billion-sensor CMOS image sensor industry in every modern smartphone.
Legal Claims Decoder (32 Numbered Claims)
The Historical Bottleneck
Why Prior Art Failed
- •Magnetic stores represented information by domain polarity in sheets, cores, or wires.
- •Electrostatic camera targets required scanning-electron-beam readout.
- •Acoustic and electromechanical delay lines held information dynamically in traveling elastic waves.