2226167

Information

• Patent Grant
• 2226167

• References
• Source

• Patent Number

  2,226,167

• Date Filed

  Not available

• Date Issued

  Tuesday, December 24, 1940
  84 years ago

• CPC

  • G01J1/14 - using comparison with a surface of graded brightness

• US Classifications

  • 356 - Optics: measuring and testing
  • 355 - Photocopying
  • 359 - Optical: systems and elements
  • 430 - Radiation imagery chemistry: process, composition, or product thereof