×

Electronic book system

  • US 5,956,048 A
  • Filed: 11/10/1997
  • Issued: 09/21/1999
  • Est. Priority Date: 11/10/1997
  • Status: Expired due to Fees
First Claim
Patent Images

1. An electronic book system, comprising:

  • a storage medium storing book data, said storage medium includinga book data memory portion, anda code bank memory portion, the code bank memory portion storing a code bank value, the code bank value initially being set at a predetermined initial value;

    a portable display unit adapted to read and display data from said storage medium, the portable display unit including a unit code memory storing a predetermined unit code value and a comparator comparing the code bank value with the unit code value; and

    coding means permitting access and display of the data stored on the storage medium by said display unit and preventing access and display of the data when the storage medium was previously read by another display unit;

    wherein when the code bank value is at said predetermined initial value, a signal indicating the unit code value is delivered to the code bank and stored thereafter as the code bank value, andwherein the portable display unit can access the data when said code bank value is equal to the unit code value and wherein access to the data is prevented when the code bank value is not equal to the unit code value.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×