Electron source
US-2025364199-A1 · Nov 27, 2025 · US
Semiconductor cathodes, e.g. cathodes with PN junction layers
Semiconductor cathodes, e.g. cathodes with PN junction layers · Cooperative Patent Classification (CPC)
Electric circuits, power, telecommunications, and semiconductors.
Related technology areas
Mapped technology topics for this CPC code.
| Metric | Value |
|---|---|
| CPC code | H01J1/308 |
| Official title | Semiconductor cathodes, e.g. cathodes with PN junction layers |
| Display label | Semiconductor cathodes, e.g. cathodes with PN junction layers |
| Total patents | 53 |
Filing trend
Year-over-year patent counts classified under this CPC code.
Filing activity over the last five years is stable.
| Year | Patents |
|---|---|
| 2015 | 15 |
| 2016 | 8 |
| 2017 | 9 |
| 2018 | 4 |
| 2019 | 4 |
| 2020 | 3 |
| 2022 | 4 |
| 2023 | 1 |
| 2024 | 2 |
| 2025 | 3 |
Representative patents
Representative publications under this CPC code from precomputed stats, or recent filings when stats are unavailable.
Field emission device, and x-ray generation device using same
US-2025364204-A1 · Nov 27, 2025 · US
Package having field emission element and x-ray device having the same
US-2025275297-A1 · Aug 28, 2025 · US
Electron emission device and electron microscope
US-12051557-B2 · Jul 30, 2024 · US
Substrate stack epitaxies for photocathodes for extended wavelengths
US-2024145202-A1 · May 2, 2024 · US
Electron emitting element and power generation element
US-11664182-B2 · May 30, 2023 · US
Plasmonic photocathode emitters at ultraviolet and visible wavelengths
US-11495428-B2 · Nov 8, 2022 · US
Electron emission device and electron microscope
US-2022216026-A1 · Jul 7, 2022 · US
Electron emitting element and power generation element
US-2022139660-A1 · May 5, 2022 · US
Methods for producing composite GaN nanocolumns and light emitting structures made from the methods
US-11322652-B2 · May 3, 2022 · US
Plasmonic photocathode emitters at ultraviolet and visible wavelengths
US-2020266019-A1 · Aug 20, 2020 · US
Photocathode including field emitter array on a silicon substrate with boron layer
US-10748730-B2 · Aug 18, 2020 · US
Electron emission device, method for manufacturing same, and method for manufacturing electronic device
US-10643815-B2 · May 5, 2020 · US
Field emission devices and methods of making thereof
US-10504772-B2 · Dec 10, 2019 · US
Passive local area saturation of electron bombarded gain
US-10312047-B1 · Jun 4, 2019 · US
Electron emission device, method for manufacturing same, and method for manufacturing electronic device
US-2019080870-A1 · Mar 14, 2019 · US
Microstructured surface with low work function
US-10186395-B2 · Jan 22, 2019 · US
Radio frequency field immersed ultra-low temperature electron source
US-10051720-B1 · Aug 14, 2018 · US
Electron emitter and light emitting apparatus comprising same
US-2018198027-A1 · Jul 12, 2018 · US
Nano vacuum gap device with a gate-all-around cathode
US-9953796-B2 · Apr 24, 2018 · US
Frequently asked questions
Answers are generated from the same data shown on this page.
- What is CPC H01J1/308?
- CPC H01J1/308 is the Cooperative Patent Classification code for “Semiconductor cathodes, e.g. cathodes with PN junction layers.”
- How many patents are filed under CPC H01J1/308 (Semiconductor cathodes, e.g. cathodes with PN junction layers)?
- Our database includes 53 publications tagged with this CPC code.
- Is patent activity under CPC H01J1/308 growing?
- Publication counts under this code: 2 in 2024 vs 3 in 2025 (latest complete years).