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DIFF Subgroup
G01J 9/04

by beating two waves of a same source but of different frequency and measuring the phase shift of the lower frequency obtained

Introduced: January 1980

Title

Titles differ between systems:

IPC: by beating two waves of the same source but of different frequency and measuring the phase shift of the lower frequency obtained

CPC: by beating two waves of a same source but of different frequency and measuring the phase shift of the lower frequency obtained

Full Title

Full titles differ between systems:

IPC:

Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength > by beating two waves of the same source but of different frequency and measuring the phase shift of the lower frequency obtained

CPC:

Measuring optical phase difference (devices or arrangements for controlling the phase of light beams G02F1/01); Determining degree of coherence; Measuring optical wavelength (spectrometry G01J3/00) > by beating two waves of a same source but of different frequency and measuring the phase shift of the lower frequency obtained

No child classifications to compare. This is a leaf node in both IPC and CPC.

Top Applicants

Top Applicants (IPC)

Class G01,2013–2023, worldwide · Source: EPO PATSTAT

  1. SGCC(STATE GRID CORPORATION OF CHINA) 41,447
  2. CHINESE ACADEMY OF SCIENCES 32,952
  3. ROBERT BOSCH DE 16,470
  4. SAMSUNG ELECTRONICS COMPANY KR 10,052
  5. SINOPEC (CHINA PETROCHEMICAL CORPORATION) 9,573
  6. ZHEJIANG UNIVERSITY 9,529
  7. GUANGDONG POWER GRID CORPORATION 8,615
  8. TSINGHUA UNIVERSITY 7,805
  9. HALLIBURTON ENERGY SERVICES GROUP US 7,796
  10. QUALCOMM US 7,171

Top Applicants (CPC)

Class G01,2013–2023, worldwide · Source: EPO PATSTAT

  1. CHINESE ACADEMY OF SCIENCES 21,460
  2. ROBERT BOSCH DE 17,801
  3. SGCC(STATE GRID CORPORATION OF CHINA) 17,347
  4. SAMSUNG ELECTRONICS COMPANY KR 13,192
  5. QUALCOMM US 9,900
  6. HALLIBURTON ENERGY SERVICES GROUP US 9,742
  7. PHILIPS ELECTRONICS NL 7,249
  8. MITSUBISHI ELECTRIC CORPORATION JP 6,503
  9. ZHEJIANG UNIVERSITY 6,414
  10. DENSO CORPORATION JP 6,382