Patents Assigned to Larry L. Ball
  • Portable map display device
    Patent number: 4437739
    Abstract: A portable display device for projecting on a built-in rear projection screen a road map, navigation chart and the like. The road map or navigation chart is in the form of one of a plurality of microfilm frames removably installed in a cut-out portion of a hollow drum in which is disposed a projection lamp. The drum is indexable in angular position and in longitudinal position such as to display an appropriate portion or frame of the microfilm.
    Type: Grant
    Filed: September 7, 1982
    Date of Patent: March 20, 1984
    Assignee: Larry L. Ball
    Inventor: John R. Haskin