Lloyd's Accumatic 100
In 1972 North American Rockwell Microelectronics Inc. became the first company to manufacture calculators with Liquid Crystal Displays.
Rockwell produced several models of similar calculators using DSM (Dynamic Scattering Mode) LCDs (Liquid Crystal Displays) and these were marketed by several companies. A DSM LCD is clear until a voltage is applied when it becomes opaque white. By energising transparent electrodes on the LCD glass, in the familiar 7-segment configuration, numbers can be displayed.
Some of these LCD calculators were AC-powered desktop models. The Lloyd's Accumatic 100 here is a battery-powered model.
Calculator energised with the display cover raised and the display illumination turned on.
Lloyd's Accumatic 100
Distinctive features: The first commercial hand-held calculator with a liquid crystal display (LCD), using a DSM (Dynamic Scattering Mode) LCD.
Display is 8 digits, DSM LCD, illuminated by a filament lamp.
Main integrated circuits - Rockwell 10362PB and 2 of 10417PB (here date coded to week 24 and week 26 of 1972).
6v (4 x D cells).
143 mm x 235 mm x 54 mm (5.6" x 9.25" x 2.1").
"Assembled in Mexico primarily of United States parts"
Lloyd's Electronics, Inc., Compton, California., U.S.A.
Pressing the red "Power" button springs the display cover open and turns on the calculator. Pressing the display cover closed switches the calculator off.
Inside the calculator showing, on the right, the filament lamp at the top and the clear plastic light pipe (shaped like half of an ellipse) to illuminate the numbers of the display.
The circuit board, with the LCD at the top and the 3 Rockwell integrated circuits.
The calculator held in the hand, showing the large size, with the display cover closed.
Rockwell manufactured this model, as reported in the journal Electronics in March 1972:
"North American Rockwell will begin delivering in June electronic calculators that are expected to sell to the consumer for about $100. Among the customers is Sears Roebuck. The calculators, which will have unique features and case designs for individual customers, will use liquid crystal displays and MOS ICs manufactured by NRMEC—North American Rockwell Microelectronics Co.
NR has contracts for more than 150,000 machines with Sears, Lloyds of California, Logic Data of Chicago, and others to be announced. And Donn L. Williams, president of NR's Electronics group, says that worldwide sales are expected to to total at least a million units a year ."
Calculator models manufactured by Rockwell for other companies were the first calculators with a Liquid Crystal Display (LCD) to go on sale (see also the Rapid Data Rapidman 1208LC desktop model).
Due to the white scattering nature of the numerals of this first generation LCD a filament lamp is used to illuminate the display through the edge from above. The lamp has a high current consumption requiring the use of four large D cells, though rechargeable ones can be used. This negates the main advantage of the low power consumption of the LCD. Other slightly later models (eg. Sharp EL-8001) used a reflective type LCD where a hood over the display with a diffusing window illuminates the numbers of the display.
The introduction of LCDs in calculators was not smooth. There was much debate about the life expectancy of the Liquid Crystal compounds used in these displays. Two of the examples here have damaged displays though one example still worked perfectly after 30 years. High temperature storage, especially, is to be avoided with these displays. There also appear to have been manufacturing problems, and it was to be 3 or 4 years before LCD technology had improved and cost dropped for it to start becoming the dominant display of calculators.
See the article "Liquid Crystal Display (LCD) Calculators" on this site for information about other early LCD calculators.
Excellent Youtube videos produced by Michiel de Boer that graphically explain these Liquid Crystal Displays are:
© Text & photographs copyright Nigel Tout 2000-2021 except where noted otherwise.