2478539

Information

• Patent Grant
• 2478539

• References
• Source

• Patent Number

  2,478,539

• Date Filed

  Not available

• Date Issued

  Tuesday, August 9, 1949
  75 years ago

• CPC

  • G11B3/70 - characterised by the selection of material or structure Processes or apparatus specially adapted for manufacturing record carriers
  • G11B3/72 - Groove formations

• US Classifications

  • 369 - Dynamic information storage or retrieval