G01N 21/431
Dip refractometers
Official title: {Dip refractometers, e.g. using optical fibres}
G01N21/431 (Dip refractometers) appears on 168 US grants and 85 published applications in this corpus.
Search patents in G01N- Granted patents
- 168
- Published applications
- 85
- Assignees
- 141
- Inventors
- 371
- Latest grant
- 17 Feb 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 2 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 3 | 0 |
| 1981 | 4 | 0 |
| 1982 | 3 | 0 |
| 1983 | 1 | 0 |
| 1984 | 2 | 0 |
| 1985 | 0 | 0 |
| 1986 | 1 | 0 |
| 1987 | 4 | 0 |
| 1988 | 1 | 0 |
| 1989 | 10 | 0 |
| 1990 | 9 | 0 |
| 1991 | 12 | 0 |
| 1992 | 8 | 0 |
| 1993 | 5 | 0 |
| 1994 | 3 | 0 |
| 1995 | 6 | 0 |
| 1996 | 3 | 0 |
| 1997 | 4 | 0 |
| 1998 | 4 | 0 |
| 1999 | 3 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 1 |
| 2002 | 3 | 1 |
| 2003 | 4 | 6 |
| 2004 | 3 | 8 |
| 2005 | 4 | 0 |
| 2006 | 5 | 3 |
| 2007 | 1 | 2 |
| 2008 | 4 | 4 |
| 2009 | 3 | 4 |
| 2010 | 4 | 4 |
| 2011 | 2 | 3 |
| 2012 | 3 | 5 |
| 2013 | 3 | 1 |
| 2014 | 2 | 2 |
| 2015 | 3 | 3 |
| 2016 | 3 | 2 |
| 2017 | 3 | 4 |
| 2018 | 7 | 5 |
| 2019 | 4 | 6 |
| 2020 | 2 | 5 |
| 2021 | 5 | 3 |
| 2022 | 2 | 7 |
| 2023 | 2 | 4 |
| 2024 | 1 | 0 |
| 2025 | 2 | 1 |
| 2026 | 2 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Apparatuses, systems, and methods for sample testing17 Feb 2026US 12,553,885 B2Hand Held Products, Inc.
- Apparatuses, systems, and methods for sample testing20 Jan 2026US 12,529,696 B2Hand Held Products, Inc.
- Dextrose concentration sensor for a peritoneal dialysis system17 Jun 2025US 12,329,892 B2Bellco SRL
- Immersed lens downhole refractometer1 Apr 2025US 12,264,581 B2Baker Hughes Oilfield Operations LLC
- Sensor for determining liquid types6 Feb 2024US 11,892,398 B2Toyoko Kagaku Co., Ltd.
- Fiber-optic seawater salinity sensor system and preparation method thereof30 Apr 2026US 2026/0118261 A1Tianjin University
- System and method for simultaneously measuring refractive index and turbidity5 Jun 2025US 2025/0179410 A1
- Immersed lens downhole refractometer5 Oct 2023US 2023/0313679 A1Baker Hughes Oilfield Operations LLC
- Refractometer, optically transmissive structure, and method of making an optically transmissive structure21 Sep 2023US 2023/0296509 A1
- Fiber optic measurement device8 Jun 2023US 2023/0175970 A1Indian Institute of Technology Madras (Iit Madras)
Most cited
By later US patents
- Optical sensor for selective detection of substances and/or for the detection of refractive index changes in gaseous, liquid, solid and porous samples262US 4,815,843 AOerlikon-Buhrle Holding AG · 1989
- Optical sensor for selective detection of substances and/or for the detection of refractive index changes in gaseous, liquid, solid and porous samples146US 5,071,248 AAsi AG · 1991
- Fiber optic detection system120US 5,362,971 ATerrascope Systems, Inc. · 1994
- Chip level waveguide sensor120US 5,439,647 AFiberChem Inc. · 1995
- Optical head probe using a gradient index lens and optical fibers107US 5,410,413 APetrometrix Ltd. · 1995