3697681

Information

• Patent Grant
• 3697681

• References
• Source

• Patent Number

  3,697,681

• Date Filed

  Not available

• Date Issued

  Tuesday, October 10, 1972
  52 years ago

• CPC

  • G09B9/32 - by projected image
  • G09B9/34 - by cathode-ray screen display

• US Classifications

  • 348 - Television
  • 434 - Education and demonstration