3617324

Information

• Patent Grant
• 3617324

• References
• Source

• Patent Number

  3,617,324

• Date Filed

  Not available

• Date Issued

  Tuesday, November 2, 1971
  53 years ago

• CPC

  • G09B3/085 - with invisibly printed correct answer; the answer being rendered visible by special optical means
  • B41M3/001 - using chemical colour-formers or chemical reactions
  • B41M5/26 - Thermography; Marking by high energetic means
  • Y10S430/145 - Infrared

• US Classifications

  • 430 - Radiation imagery chemistry: process, composition, or product thereof
  • 101 - Printing
  • 427 - Coating processes
  • 434 - Education and demonstration