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 filing trajectory.

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

8,986
US patents granted: C03
Parent CPC class: 20
Active assignees: +24%
5-yr velocity

The verdict

Chemical Composition OF Glasses ranks #180 of 670 CPC technology areas - 8,986 US patents granted since 2015, with filing up 24% over five years.

#180
of 670 CPC technology areas: 8,986
US patents granted, 2015–2025: Corning Incorporated
leading assignee (1,507): +24%
filing velocity, last 5 yrs

Top assignee: Corning Incorporated (1,507 patents)

CPC subclass C03C - 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 - covers 8,986 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class C03 (GLASS; MINERAL OR SLAG WOOL). See our CPC classification guide for how the system works.

The competitive landscape in C03C is shaped by 20 distinct companies actively filing in this space. Corning Incorporated leads with 1,507 patents, followed by Schott Ag at 300 grants and AGC Inc. at 288.

Filing activity in C03C is up 24% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is C03C innovation accelerating?

US utility-patent grants per year in C03C, 2015–2025 - recent five years are up 24% versus 2015–2019.

Corning Incorporated

1,507
Schott

300
Agc

288
Saint-gobain Glass Fr…

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

About This Class

CPC subclass C03C belongs to class C03.

8,986 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 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).

Frequently Asked Questions

What is CPC class C03C?

CPC subclass C03C covers 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. It belongs to CPC class C03 (GLASS; MINERAL OR SLAG WOOL), with 8,986 US utility patents granted since 2015.

How many patents have been filed in C03C?

8,986 US utility patents were granted in CPC subclass C03C between 2015 and 2025, based on USPTO PatentsView data.

Which company holds the most patents in C03C?

Corning Incorporated leads C03C with 1,507 patents, making it the most active assignee in this technology area.

How is patent data for C03C 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., C03) is a broad technology category. Subclasses like C03C 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.