Mini electronic calculator with blackboard display format
US4016411A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 29, 1976 |
| Grant date | Apr 5, 1977 |
| Priority date | — |
| Expiry date | Jan 29, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F15/0225
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A mini electronic calculator adapted to assist children in acquiring the rudiments of arithmetic. The keyboard of the calculator is provided with three parallel sets of keys, the upper set being a row of digit keys for entering a first complete number, and the middle set being a corresponding row of digit keys for entering a second complete number. The lower set includes plus and minus sign function keys and an equal sign key. The calculator display is in a blackboard format and has three parallel groups of LED display stations, the upper group of which is formed by a row of digit stations for presenting the first complete number entered by actuating the keys in the upper keyboard set. The second group is formed by a lead station for presenting a plus or minus sign, depending on which function key is actuted, followed by a row of digit stations for presenting the second complete number entered by actuating the keys in the middle set. The third group is separated on the blackboard display from the second group by a permanent summation line and is formed by a lead station for presenting the equal sign, followed by a row of digit stations for presenting the result of the computation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.