CPC technology class · C03

C03C - Chemical Composition Of Glasses

Chemical composition of glasses, glazes or vitreous enamels; surface treatment of glass; surface treatment of fibres or filaments made from glass, minerals or slags; joining glass to glass or other materials. 8,986 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

8,986
US patents granted: #1/2
in C03: 65.9%
C03 class share: +6%
5-yr velocity

The verdict

According to USPTO PatentsView, Chemical Composition Of Glasses ranks #180 of 670 CPC technology areas - 8,986 US patents granted since 2015, with recorded grant volume up 6% over five years.

#180
of 670 CPC technology areas: 8,986
US patents granted, 2015–2025: Corning Incorporated
leading assignee (1,507): +6%
grant velocity, last 5 yrs

How C03C's grant cadence moved

Between 2020–2024, C03C recorded 4,029 grants versus 3,790 in 2015–2019 (+6% equal-window velocity). Across complete years, output peaked in 2019 at 907 grants and bottomed in 2015 at 663 (+37% peak-over-trough). Lead assignee Corning Incorporated holds 16.8% of the class ; the top three share 23.3%.

Leaderboard read

C03C concentration, lead at 16.8%

Corning Incorporated leads this historical grant record at 16.8% of C03C - foreign corporation assignees hold 51% of class grants (2,866 of 5,671). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 16.8%
Top three share: 23.3%
Lead over #2: 1,207

Where C03C sits inside C03

Among 2 subclasses in C03 (GLASS; Mineral OR Slag Wool), C03C ranks #1 and holds 65.9% of the parent class's 13,637 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

C03B 4,651

Rising assignees active in C03C

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 Rockwool A/S 21x 0 → 21 company-wide · 12 in C03C
#2 ACR II Glass America Inc. 16x 0 → 16 company-wide · 9 in C03C
#3 Tunghsu Technology Group Co., Ltd. 10x 0 → 10 company-wide · 6 in C03C
#4 Nelumbo Inc. 8.00x 1 → 8 company-wide · 6 in C03C
#5 Tunghsu Group Co., Ltd. 7.00x 2 → 14 company-wide · 9 in C03C

C03C grants by year, peak 2019 (907)

US utility-patent grants per year in C03C, 2015–2025 - recent five years are up 6% versus 2015–2019.

Corning Incorporated

1,507
Schott

300
Agc

288
Saint-gobain Glass…

218
Nippon Electric Glass

194
Guardian Glass

173
Asahi Glass

110
Agc Glass Europe

106
Guardian Industries

104
Hoya

93
Nippon Sheet Glass

73
Pilkington Group

67

What this shows Corning Incorporated is the most active filer in C03C, holding 1,507 of the 8,986 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 C03C
Rank	Company	Patents in C03C
#1	Corning Incorporated	1,507
#2	Schott AG	300
#3	AGC Inc.	288
#4	Saint-gobain Glass France	218
#5	Nippon Electric Glass Co., Ltd.	194
#6	Guardian Glass, LLC	173
#7	Asahi Glass Co., Ltd.	110
#8	AGC Glass Europe	106
#9	Guardian Industries Corp.	104
#10	Hoya Corporation	93
#11	Nippon Sheet Glass Company, Limited	73
#12	Pilkington Group Limited	67
#13	Owens-Brockway Glass Container Inc.	66
#14	Ivoclar Vivadent AG	57
#15	Vitro Flat Glass LLC	57
#16	Heraeus Quarzglas GMBH & Co. KG	56
#17	Johns Manville	51
#18	View, Inc.	46
#19	PPG Industries Ohio, Inc.	44
#20	Saint-gobain Isover	44

Footprint here vs. claim strategy

Each dot is a leading C03C 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 C03C assignees by class footprint. Bubble size = patents in C03C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near C03C's 8,986-grant footprint

Nationwide nearest neighbors for C03C (#180 of 670 by volume ; lead share 16.8%) - not the C03 parent-class siblings above.

Nearest by grant volume

B08B 9,052 F25D 8,866 A23V 9,116 G01K 8,803

Nearest by lead-assignee share

H01T 16.7% D05B 16.6% F25C 16.4% A24B 16.3%

Questions about C03C

Which company holds the most patents in C03C?

Corning Incorporated leads C03C with 1,507 patents (16.8% of the subclass). By PatentsView assignee type, foreign corporations account for 51% of class grants.

Which C03C assignees grew fastest recently?

Among assignees with ≥5 grants in C03C, Rockwool A/S shows the highest company-wide grant multiple (21x: 0 grants in 2019–2021 → 21 in 2022–2024) while holding 12 patents in this subclass. Growth is company-wide, not class-only.

How does C03C compare inside parent class C03?

Inside C03 (GLASS; Mineral OR Slag Wool), C03C ranks #1 of 2 subclasses by grant volume and holds 65.9% of the parent class total. The largest sibling is C03B (4,651 grants).

What to do with this data

C03C in context - here's where to go next.

Corning Incorporated leads C03C with 1,507 grants in this class. See full portfolio
C03C ranks #180 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class C03, the largest sibling subclass is C03B with 4,651 grants. Explore C03B

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

Methodology - C03C figures are USPTO PatentsView granted-utility totals for this subclass (8,986 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.