How Texas Instruments Invented the Handheld Electronic Calculator
This 1972 patent describes the architecture for the first truly portable, battery-powered electronic calculator that could fit in a pocket.
Original patent title: “Miniature electronic calculator”
This 1972 patent describes the architecture for the first truly portable, battery-powered electronic calculator that could fit in a pocket. Granted to Texas Instruments Inc in 1974 with 74 claims and 18 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The patent details a system that shrinks bulky desktop calculator components into a handheld device. It uses an integrated semiconductor circuit array—a single chip—to handle memory storage, arithmetic operations like addition and division, and control signaling. The design stacks the keyboard, the circuit array, and the display in parallel planes to minimize the device's footprint. This allows the calculator to process multi-digit numbers and display results on a small screen or via a thermal printer while running on battery power.
The gap
What does this patent NOT cover?
- Does not cover non-electronic or mechanical calculators (e.g., slide rules or abacuses).
- Does not cover calculators that require external power sources or wall outlets.
- Does not cover computing devices that lack a physical keyboard input mechanism.
- Does not cover general-purpose computers or microprocessors not specifically configured for arithmetic calculation.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation was the spatial arrangement of the components. By aligning the keyboard and the integrated semiconductor array in parallel planes within a pocket-sized housing, the inventors achieved a level of density that made portable digital math possible for the first time.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Texas Instruments TI-2500 Datamath
Early handheld electronic calculators of the 1970s
Why it matters
The bigger picture
This invention marked the transition of computing from room-sized machines to personal, portable tools. It proved that complex integrated circuits could be mass-produced for consumer electronics, paving the way for the modern smartphone and all handheld digital devices that followed.
Filed
December 21, 1972
Granted
June 25, 1974
Market context
Who's building on this
Companies in this space
Texas Instruments remains a major player in semiconductor design and embedded processing. The architecture established here is the direct ancestor of the system-on-a-chip designs used by companies like Apple, Qualcomm, and Samsung to power modern mobile devices.
Market impact
This patent triggered a massive shift in the consumer electronics market, effectively killing the mechanical calculator industry within a few years. It established the viability of the handheld device category, leading to the rapid miniaturization of consumer technology throughout the 1970s and 80s.
Claim 1 — Plain English
What this patent covers
The patent details a system that shrinks bulky desktop calculator components into a handheld device. It uses an integrated semiconductor circuit array—a single chip—to handle memory storage, arithmetic operations like addition and division, and control signaling. The design stacks the keyboard, the circuit array, and the display in parallel planes to minimize the device's footprint. This allows the calculator to process multi-digit numbers and display results on a small screen or via a thermal printer while running on battery power.
The clever bit
The innovation was the spatial arrangement of the components. By aligning the keyboard and the integrated semiconductor array in parallel planes within a pocket-sized housing, the inventors achieved a level of density that made portable digital math possible for the first time.
What it does not cover
- Does not cover non-electronic or mechanical calculators (e.g., slide rules or abacuses).
- Does not cover calculators that require external power sources or wall outlets.
- Does not cover computing devices that lack a physical keyboard input mechanism.
- Does not cover general-purpose computers or microprocessors not specifically configured for arithmetic calculation.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Moderate
Citation count
26/40
Moderately cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$35K – $111K
Midpoint $69K · expired or expiring · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
74 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Kilby, J., Merryman, J., & Van, T. J. (1974). How Texas Instruments Invented the Handheld Electronic Calculator (U.S. Patent No. 3,819,921). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/3819921/barcode-upc-scanner
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Texas Instruments Invented the Handheld Electronic Calculator cover?
This 1972 patent describes the architecture for the first truly portable, battery-powered electronic calculator that could fit in a pocket.
Who owns patent US 3819921?
Texas Instruments Inc owns this patent, granted in 1974.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 3819921 cited by?
This patent has been cited by 18 later patents that build on its ideas.
What problem does this patent solve?
This invention marked the transition of computing from room-sized machines to personal, portable tools. It proved that complex integrated circuits could be mass-produced for consumer electronics, paving the way for the modern smartphone and all handheld digital devices that followed.
What does this patent NOT cover?
Does not cover non-electronic or mechanical calculators (e.g., slide rules or abacuses).
Same assignee
More from Texas Instruments Inc
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