Re-reading the 1973 Bell Labs US3792322A by Willard S. Boyle and George E. Smith — the 'Buried channel charge coupled devices' patent that became the origin of modern smartphone cameras, astronomical observation, and medical imaging sensors

About excavation memos: "Excavation memos" in this series record candidate summaries at the stage where the primary URL has been confirmed. This memo retrieves the title, inventors, assignees, dates, and Claim 1 from Google Patents, but the full specification (the patent-paper lineage with the 1969 Boyle/Smith Bell System Technical Journal article, the commercialization process at Sony / Kodak / Sanyo, and the generational shift to CMOS image sensors) is unread. Only confirmed facts are stated; speculation is marked as such.

Why excavate this

The CCD (Charge Coupled Device) lives on as the principal image sensor for (a) astronomical telescopes (Hubble, James Webb, Chile's ELT family), (b) medical imaging (X-ray, fluorescence microscopy, electron microscopy), and (c) industrial measurement (machine vision, X-ray inspection). On the consumer side—smartphones, DSLRs, dashcams, surveillance—the field migrated almost entirely to CMOS image sensors during the 2010s. This patent, US3792322A, is the ancestral form of the entire image-sensor lineage, and the starting point of the image-sensor businesses at Sony Semiconductor Solutions (No. 1 worldwide CMOS share), Samsung System LSI, OmniVision, and SK Hynix.

As the charge-cage slot of Day 19's three-piece set 'Cage Patents — confining electrons, charge, and molecules,' this memo joins ep70 flash memory (electron cage) and ep72 hyaluronic-acid crosslinked gel (molecular cage). The Claim 1 verbatim says "potential minima" (potential well) exist physically inside the medium—the patent-claim language for a charge cage.

Patent basic information

• Patent number: US3792322A
• Title: Buried channel charge coupled devices
• Inventors: Willard Sterling Boyle / George Elwood Smith (two co-inventors)
• Original Assignee: Individual (assignment unrecorded at filing)
• Current Assignee: Individual (but a Certificate of Correction assigned it to Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey)
• Priority Date / Filing Date: 1973-04-19
• Grant Date: 1974-02-12
• Status: Expired - Lifetime (expired in 1991)

DB match: "Bell Telephone Laboratories, Willard S. Boyle / George E. Smith, 2009 Nobel Prize" — all fields match, 13th match confirmed in the cumulative DB-error correction sequence (Day 8-18), following Day 18 ep67 (Bell Labs solar cell) — two consecutive Bell Labs matches.

Special case in transfer history: the Original Assignee field reads "Individual" because the patent was filed under the inventors' personal names, with the Bell Labs assignment added later as a Certificate of Correction. This may relate to AT&T's internal patent-filing protocol changes in the 1970s, but primary sources are unconfirmed.

Claim 1 (verbatim from primary source)

The Claim 1 retrieved from Google Patents:

A charge coupled device comprising: a planar charge storage medium; a multiplicity of discrete electrode field plates arranged adjacent to the charge storage medium, each capable when electrically biased of forming an associated charge storage site within the charge storage medium, the field plates being spaced sequentially in a direction parallel to the plane of the charge storage medium with each adjacent to at least two other field plates so that, with appropriate electrical bias applied to at least two of said field plates, electrical charge can be made to pass controllably between selected charge storage sites and ultimately to a detection site; input means for introducing mobile electrical charge into the charge storage medium; detection means for detecting the presence or absence of charge in the storage medium at a detection site; charge transfer means including said field plates for transferring within the storage medium, the electrical charge between storage sites, and to the detection site; the invention characterized in that the storage medium is bounded on all sides with electrical barriers except for a limited area, ohmic contact means to the storage medium at said limited area for electrically biasing the storage medium with respect to said barriers to deplete the storage medium and, with the electrical bias applied to the field plates, to create potential minima for the stored electrical charge, the potential minima existing physically within the storage medium, interior of the boundary electrical barriers whereby said charge storage sites exist physically within said interior.

Four core points of Claim 1:

1. Planar charge-storage medium + many electrode field plates: many electrodes are arranged on the medium, and electrical bias creates charge-storage sites. This is the prototype of the modern CCD pixel array.
2. Medium surrounded on all sides by electrical barriers + ohmic contact at a limited area: the medium is electrically confined. This is the physical expression of the patent's "buried channel."
3. "potential minima existing physically within the storage medium, interior of the boundary electrical barriers": this is the verbatim patent-claim expression of a charge cage. With electrical bias, potential minima are created physically inside the medium, and charge is trapped in those wells. The basis on which the Day 19 Cage Patents axis stands.
4. Controlled charge movement and detection: electrical bias on the electrode field plates moves charge between storage sites and ultimately reads it out at the detection site. This is the etymological origin of "charge coupled."

Note: this patent is distinct from the 1970 Boyle/Smith joint patent US3796927A ("Information storage utilizing thermomagnetic-magnetooptical processes") and the 1969 Bell System Technical Journal paper "Charge Coupled Semiconductor Devices" (BSTJ 49(4), 587-593) by the same two authors. US3792322A covers the buried-channel improvement to CCDs. The lineage runs surface-channel CCD (earliest) → buried-channel CCD (this patent) → multi-pixel CCD (1976~) → CMOS image sensor (1990s onward), and this is one of the important nodes in that chain.

Forty years from 1969 to 2009

• 1969-10: Boyle/Smith conceive the CCD concept at a Bell Labs whiteboard in roughly one hour (industry secondary sources, recounted in both Nobel lectures)
• 1969-12: BSTJ paper "Charge Coupled Semiconductor Devices" published
• 1970-08: Boyle/Smith run the first CCD operation demo (internal Bell Labs)
• 1973-04-19: this patent US3792322A filed (buried-channel improvement)
• 1974-02-12: this patent granted
• 1974-1979: Fairchild / Texas Instruments / RCA attempt CCD commercialization
• 1980: Sony mass-produces the video-camera CCD "ICX008," industry's first home camcorder CCD
• 1985-1995: Sony / Kodak / Sanyo / Toshiba mass-production race for digital-camera CCDs
• Late 1990s: CMOS image sensors begin commercialization (Photobit, later Aptina / acquired by Sony, etc.)
• 2010s: smartphones and DSLRs see CMOS fully replace CCDs; CCDs persist in astronomical, medical, and industrial measurement
• 1991-04-19: this patent expires (US lifetime)
• 2009-12-08: Boyle / Smith / Charles K. Kao (optical fiber) jointly receive the Nobel Prize in Physics; Boyle/Smith for the CCD invention

Modern correspondence hypothesis

Center of gravity: 2 rows of "Same" (the CCD line in active service, shift-register transfer). Even 30+ years after expiry, this patent persists in astronomical observation and medical imaging-sensor fields.

Note: 1 row of "Analogy" (CMOS image sensor pixel array) is structurally similar but each-pixel readout circuits put CMOS outside Claim 1's scope.

To be precise (concise three items)

Confirmed facts:

• US3792322A, title "Buried channel charge coupled devices," inventors Willard Sterling Boyle + George Elwood Smith two names, Original Assignee Individual (Certificate of Correction to Bell Telephone Laboratories), Priority/Filing 1973-04-19, Grant 1974-02-12, retrieved via WebFetch from Google Patents
• Full text of Claim 1 retrieved. "potential minima existing physically within the storage medium, interior of the boundary electrical barriers" verbatim confirmed.

Author's interpretation:

• "Charge cage slot of the Cage Patents axis" is an editorial decision in this session. Reading Claim 1's "potential minima" as a "charge cage" is the author's interpretation.
• Positioning this as "the precursor of modern CMOS image sensors" is a lineage placement; CMOS is a separate-line invention. Reading it as a "preceding example" is more precise.

Unconfirmed:

• Full specification, figures, detailed embodiments, alternative embodiments
• Full text of the 1969 BSTJ paper "Charge Coupled Semiconductor Devices" (unretrieved here)
• Issue date and contents of the Certificate of Correction (the primary source for the Bell Labs assignment correction)
• Patent-licensing history of CCD commercialization at Sony / Kodak / Fairchild
• Detailed grounds for the 2009 Nobel Prize award

References

• US Patent US3792322A (Google Patents): https://patents.google.com/patent/US3792322A/en
• 2009 Nobel Prize in Physics overview (Boyle/Smith CCD invention): https://www.nobelprize.org/prizes/physics/2009/

Day 19 three-piece set 'Cage Patents'

• Note #4: 1980 Masuoka + Iizuka flash memory US4531203A — electrons confined in a floating-gate cage
• Memo #6 (this article): 1973 Bell Labs Boyle/Smith CCD US3792322A — charge confined in a potential-minima cage
• Cosmetic Memo #2: 1985 Balazs/Leshchiner crosslinked hyaluronic-acid gel US4636524A — drug confined in a molecular cage