2340141

Information

• Patent Grant
• 2340141

• References
• Source

• Patent Number

  2,340,141

• Date Filed

  Not available

• Date Issued

  Tuesday, January 25, 1944
  80 years ago

• CPC

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

• US Classifications

  • 356 - Optics: measuring and testing