CPC technology class · G21

G21K - Techniques FOR Handling Particles OR Ionising Radiation

Techniques for handling particles or ionising radiation not otherwise provided for; irradiation devices; gamma ray or x-ray microscopes. 3,019 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

Compiled byPlainPatent Editorial, US Patent Intelligence Editorial Team · May 15, 2026

3,019
US patents granted: G21
Parent CPC class: 20
Active assignees: -11%
5-yr velocity

The verdict

Techniques FOR Handling Particles OR Ionising Radiation ranks #313 of 670 CPC technology areas - 3,019 US patents granted since 2015, with filing down 11% over five years.

#313
of 670 CPC technology areas: 3,019
US patents granted, 2015–2025: Carl Zeiss Smt
leading assignee (130): -11%
filing velocity, last 5 yrs

Top assignee: Carl Zeiss SMT Gmbh (130 patents)

CPC subclass G21K - TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES - covers 3,019 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING). See our CPC classification guide for how the system works.

The competitive landscape in G21K is shaped by 20 distinct companies actively filing in this space. Carl Zeiss SMT Gmbh leads with 130 patents, followed by ASML Netherlands B.v. at 85 grants and Xyleco, Inc. at 48.

Filing activity in G21K is down 11% over the past five years versus 2015-2019, a relatively steady filing pace. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is G21K innovation accelerating?

US utility-patent grants per year in G21K, 2015–2025 - recent five years are down 11% versus 2015–2019.

Carl Zeiss Smt

130
Asml Netherlands B V

85
Xyleco

48
Varian Medical Systems

44
Shanghai United Imagi…

42
Gigaphoton

42
Hamamatsu Photonics K…

38
Siemens Healthcare

33
Sigray

28
Nuctech

26
Uchicago Argonne

25
Rapiscan Systems

23

What this shows Carl Zeiss Smt is the most active filer in G21K, holding 130 of the 3,019 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass G21K
Rank	Company	Patents in G21K
#1	Carl Zeiss SMT Gmbh	130
#2	ASML Netherlands B.v.	85
#3	Xyleco, Inc.	48
#4	Varian Medical Systems, Inc.	44
#5	Shanghai United Imaging Healthcare Co., Ltd.	42
#6	Gigaphoton Inc.	42
#7	Hamamatsu Photonics K.k.	38
#8	Siemens Healthcare Limited	33
#9	Sigray, Inc.	28
#10	Nuctech Company Limited	26
#11	Uchicago Argonne, Llc	25
#12	Rapiscan Systems, Inc.	23
#13	Neuboron Medtech Ltd.	23
#14	Ionq, Inc.	22
#15	Light Field Lab, Inc.	20
#16	Rigaku Corporation	18
#17	Accuray Incorporated	18
#18	Siemens Medical Solutions USA, Inc.	17
#19	Coldquanta, Inc.	17
#20	Hologic, Inc.	14

About This Class

CPC subclass G21K belongs to class G21.

3,019 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading G21K assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 G21K assignees by class footprint. Bubble size = patents in G21K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class G21K?

CPC subclass G21K covers TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES. It belongs to CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING), with 3,019 US utility patents granted since 2015.

How many patents have been filed in G21K?

3,019 US utility patents were granted in CPC subclass G21K between 2015 and 2025, based on USPTO PatentsView data.

Which company holds the most patents in G21K?

Carl Zeiss SMT Gmbh leads G21K with 130 patents, making it the most active assignee in this technology area.

How is patent data for G21K collected?

Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.

What is the difference between CPC class and subclass?

A CPC class (e.g., G21) is a broad technology category. Subclasses like G21K provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.