发明名称 Angular twilight clock
摘要 A method and apparatus for displaying time, the day sequence for the beginning and ending of twilight, sunrise and sunset in pie-shaped section on a circular clock face. A corresponding day sequence is retrieved from a memory and presented on a circular clock face in pie-shaped sections that represent twilight, day and night for a particular coordinate position and calendar date.
申请公布号 US7218575(B2) 申请公布日期 2007.05.15
申请号 US20030698758 申请日期 2003.10.31
申请人 ROSEVEAR JOHN M 发明人 ROSEVEAR JOHN M.
分类号 G04B19/22;G04G9/02;G04G9/04 主分类号 G04B19/22
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