CPC technology class · F21

F21W - Indexing Scheme Associated With Subclasses F21k

Indexing scheme associated with subclasses f21k, f21l, f21s and f21v, relating to uses or applications of lighting devices or systems. 6,556 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

6,556
US patents granted: #5/6
in F21: 9.1%
F21 class share: +25%
5-yr velocity

The verdict

According to USPTO PatentsView, Indexing Scheme Associated With Subclasses F21k ranks #218 of 670 CPC technology areas - 6,556 US patents granted since 2015, with recorded grant volume up 25% over five years.

#218
of 670 CPC technology areas: 6,556
US patents granted, 2015–2025: Koito Manufacturing
leading assignee (157): +25%
grant velocity, last 5 yrs

How F21W's grant cadence moved

Between 2020–2024, F21W recorded 3,306 grants versus 2,643 in 2015–2019 (+25% equal-window velocity). Across complete years, output peaked in 2020 at 810 grants and bottomed in 2015 at 342 (+137% peak-over-trough). Lead assignee Koito Manufacturing Co., Ltd. holds 2.4% of the class ; the top three share 5.9%.

Leaderboard read

F21W concentration, lead at 2.4%

Koito Manufacturing Co., Ltd. leads this historical grant record at 2.4% of F21W - foreign corporation assignees hold 52% of class grants (2,149 of 4,094). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 2.4%
Top three share: 5.9%
Lead over #2: 33

Where F21W sits inside F21

Among 6 subclasses in F21 (Lighting), F21W ranks #5 and holds 9.1% of the parent class's 72,153 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F21V 23,679 F21Y 17,865 F21S 15,705 F21K 7,021 F21L 1,327

Rising assignees active in F21W

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

#1 Korrus, Inc. 71x 0 → 71 company-wide · 6 in F21W
#2 HLI Solutions, Inc. 46x 0 → 46 company-wide · 5 in F21W
#3 Hubbell Lighting, Inc. 32x 0 → 32 company-wide · 5 in F21W
#4 Goodrich Lighting Systems GmbH & Co. KG 29x 0 → 29 company-wide · 20 in F21W
#5 Aputure Imaging Industries Co., Ltd. 13x 2 → 26 company-wide · 9 in F21W

F21W grants by year, peak 2020 (810)

US utility-patent grants per year in F21W, 2015–2025 - recent five years are up 25% versus 2015–2019.

Koito Manufacturing

157
Valeo Vision

124
Signify Holding B V

106
Hyundai Mobis

87
Stanley Electric

75
Willis Electric

70
Cree

68
Guangzhou Haoyang

68
Robe lighting s r o

67
Sl

58
Hasco Vision…

55
Zkw Group

54

What this shows Koito Manufacturing is the most active filer in F21W, holding 157 of the 6,556 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 F21W
Rank	Company	Patents in F21W
#1	Koito Manufacturing Co., Ltd.	157
#2	Valeo Vision	124
#3	Signify Holding B.V.	106
#4	Hyundai Mobis Co., Ltd.	87
#5	Stanley Electric Co., Ltd.	75
#6	Willis Electric Co., Ltd.	70
#7	Cree, Inc.	68
#8	Guangzhou Haoyang Electronic Co., Ltd.	68
#9	Robe lighting s.r.o.	67
#10	SL Corporation	58
#11	Hasco Vision Technology Co., Ltd.	55
#12	ZKW Group GmbH	54
#13	Ichikoh Industries, Ltd.	54
#14	Cooper Technologies Company	52
#15	Hella GmbH & Co. KGaA	52
#16	L&L Candle Company, LLC	49
#17	Hubbell Incorporated	45
#18	Philips Lighting Holding B.V.	43
#19	Lumileds LLC	41
#20	Osram GmbH	40

Footprint here vs. claim strategy

Each dot is a leading F21W 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 F21W assignees by class footprint. Bubble size = patents in F21W. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F21W's 6,556-grant footprint

Nationwide nearest neighbors for F21W (#218 of 670 by volume ; lead share 2.4%) - not the F21 parent-class siblings above.

Nearest by grant volume

A61G 6,566 A47C 6,586 F04C 6,508 C11D 6,504

Nearest by lead-assignee share

F03G 2.4% G01J 2.4% G05D 2.4% A01G 2.4%

Questions about F21W

Which company holds the most patents in F21W?

Koito Manufacturing Co., Ltd. leads F21W with 157 patents (2.4% of the subclass). By PatentsView assignee type, foreign corporations account for 52% of class grants.

Which F21W assignees grew fastest recently?

Among assignees with ≥5 grants in F21W, Korrus, Inc. shows the highest company-wide grant multiple (71x: 0 grants in 2019–2021 → 71 in 2022–2024) while holding 6 patents in this subclass. Growth is company-wide, not class-only.

How does F21W compare inside parent class F21?

Inside F21 (Lighting), F21W ranks #5 of 6 subclasses by grant volume and holds 9.1% of the parent class total. The largest sibling is F21V (23,679 grants).

What to do with this data

F21W in context - here's where to go next.

Koito Manufacturing Co., Ltd. leads F21W with 157 grants in this class. See full portfolio
F21W ranks #218 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class F21, the largest sibling subclass is F21V with 23,679 grants. Explore F21V

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - F21W figures are USPTO PatentsView granted-utility totals for this subclass (6,556 grants in the tracked window).

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.