2399992

Information

• Patent Grant
• 2399992

• References
• Source

• Patent Number

  2,399,992

• Date Filed

  Not available

• Date Issued

  Tuesday, May 7, 1946
  78 years ago

• CPC

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

• US Classifications

  • 355 - Photocopying
  • 114 - Ships
  • 353 - Optics: image projectors