How Amorphous Silicon Changed Solar Power
This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells.
Original patent title: “Semiconductor device having a body of amorphous silicon”
This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells. Granted to RCA Corp in 1977 with 22 claims and 197 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The patent details a method for creating semiconductor devices using amorphous silicon, which is silicon that lacks a rigid, repeating crystal structure. By using a process called glow discharge in silane gas, the inventors created a material that could form effective electronic junctions. Specifically, the patent claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → devices where this amorphous silicon is paired with metallic regions or other semiconductor layers to create barriers that generate a space charge region. This allows the device to capture solar radiation and convert it into electricity, or function as a basic electronic component.
The gap
What does this patent NOT cover?
- Does not cover crystalline silicon, which is the standard material used in most traditional computer chips.
- Does not cover any manufacturing process that does not use a glow discharge in silane gas.
- Does not cover devices where the amorphous silicon layer is thicker than one micron if the specific electronic performance claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → are not met.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The invention turned the 'defect' of amorphous silicon—its lack of a crystal lattice—into a feature by showing that it could be doped and manipulated to create functional junctions at a fraction of the cost of crystalline alternatives.
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
Thin-film solar panels
Pocket calculator solar cells
Flexible solar modules
Why it matters
The bigger picture
Before this, solar cells were almost exclusively made from expensive, high-purity crystalline silicon. This patent proved that a disordered, cheaper-to-produce material could still perform the essential task of generating electricity from light, paving the way for the thin-film solar panels we see today.
Filed
July 30, 1976
Granted
December 20, 1977
Market context
Who's building on this
Companies in this space
The technology pioneered by RCA is now the foundation for the entire thin-film photovoltaic industry. Companies like First Solar and various manufacturers of consumer-grade solar electronics continue to refine the deposition processes originally explored in this era.
Market impact
This patent helped launch the thin-film solar industry, providing a lower-cost alternative to expensive silicon wafers. It enabled the integration of solar power into small consumer devices and set the stage for large-scale, flexible solar energy harvesting.
Claim 1 — Plain English
What this patent covers
The patent details a method for creating semiconductor devices using amorphous silicon, which is silicon that lacks a rigid, repeating crystal structure. By using a process called glow discharge in silane gas, the inventors created a material that could form effective electronic junctions. Specifically, the patent claims devices where this amorphous silicon is paired with metallic regions or other semiconductor layers to create barriers that generate a space charge region. This allows the device to capture solar radiation and convert it into electricity, or function as a basic electronic component.
The clever bit
The invention turned the 'defect' of amorphous silicon—its lack of a crystal lattice—into a feature by showing that it could be doped and manipulated to create functional junctions at a fraction of the cost of crystalline alternatives.
What it does not cover
- Does not cover crystalline silicon, which is the standard material used in most traditional computer chips.
- Does not cover any manufacturing process that does not use a glow discharge in silane gas.
- Does not cover devices where the amorphous silicon layer is thicker than one micron if the specific electronic performance claims are not met.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Moderate
Citation count
40/40
Highly cited
Claim breadth
15/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
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
$68K – $218K
Midpoint $137K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
22 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Carlson, D. E. (1977). How Amorphous Silicon Changed Solar Power (U.S. Patent No. 4,064,521). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4064521/semiconductor-device-having-a-body-of-amorphous-silicon
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US4064521"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4965188 · 1990
How to Make Many Copies of a DNA Piece with Heat
This patent describes the Polymerase Chain Reaction (PCR) method, a technique to make millions of copies of a specific DNA segment using a heat-resistant enzyme and repeated temperature changes.
Cetus Corp
US 4235871 · 1980
How to Encapsulate Active Materials in Lipid Bubbles Efficiently
This patent describes a method for trapping biologically active substances inside tiny, multi-layered fat bubbles called liposomes, using a specific water-in-oil emulsion and gel-forming process to improve how much material gets captured.
Individual
Semantically similar
You might also find these interesting
US 2780765 · 1957 · Bell Telephone Laboratories Inc
How the First Practical Silicon Solar Cell Works
US 3102230 · 1963 · Bell Telephone Laboratories Inc
The Invention of the Modern Field-Effect Transistor
US 2569347 · 1951 · Bell Telephone Laboratories Inc
The Invention of the Junction Transistor
US 3322485 · 1967 · RCA Corp
How Liquid Crystal Displays (LCDs) Were Invented
More to explore
More in Energy & Clean Tech
US RE49155 · 2022 · Halliburton Energy Services Inc
Electric or Natural Gas Blending and Pumping for Oil Wells
US 11436484 · 2022 · Nvidia Corp
Nvidia's Method for Training Self-Driving Car AI in Simulations
US 11840398 · 2023 · Titan Trailers Inc
How Titan Trailers Builds Stronger, Smoother Cargo Containers
US 2708656 · 1955
How the First Nuclear Reactor Works
New to patents?
Common Questions
Frequently Asked Questions
What does How Amorphous Silicon Changed Solar Power cover?
This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells.
Who owns patent US 4064521?
RCA Corp owns this patent, granted in 1977.
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 4064521 cited by?
This patent has been cited by 197 later patents that build on its ideas.
What problem does this patent solve?
Before this, solar cells were almost exclusively made from expensive, high-purity crystalline silicon. This patent proved that a disordered, cheaper-to-produce material could still perform the essential task of generating electricity from light, paving the way for the thin-film solar panels we see today.
What does this patent NOT cover?
Does not cover crystalline silicon, which is the standard material used in most traditional computer chips.
Same assignee
More from RCA Corp
Patent monitoring