The world's first wristwatch with a modern LCD display!
This Gruen Teletime was the world's first wristwatch using a modern "field effect" liquid crystal display. The Gruen Teletime came out in 1973, less than a year after the Pulsar P1, which won the title of the world's first digital watch. I retrospect, the Gruen Teletime was remarkably advanced for the time, which is evident from the fact that the Teletime looks almost ordinary and non-descript today. In addition, many Teletimes continue to run 40 years later whereas not a single known example of the 400 original Pulsar P1s is known to be running using the original module. Unfortunately, this superior engineering didn't save Gruen, which ceased producing watches in 1977, only 4 years after the Teletime.
Gruen Teletime Advertisement from July 1973
The Gruen Teletime featured the first modern liquid crystal display used in a wristwatch, which is almost identical to the displays commonly used today in wristwatches and most other forms of electronic gadgets.
The "field effect" LCD display in the Teletime applies a tiny current to a thin sheet of liquid crystal material, causing the liquid crystals to align, "polarizing" the light that passes through. When the light passes through another polarizer, the display turns dark where the liquid crystals are aligned and remains a lighter color where the liquid crystals are in their natural random orientation. These electronically controlled black on grey regions are arranged to form digits. A four digit time display like the one on the Teletime has three seven segement digits, one two segment digit and a colon, for a total of 24 independently controlled display regions. This technology has continued to be used almost unchanged from its original form 40 years ago and will probably continue for a very long time.
Gruen Teletime Prototype with Dynamic Scattering Mode (DSM) LCD Display
The Teletime was the first successful digital watch with an LCD display (made by ILIXCO of Cleveland, Ohio). It should be noted, however, the title of "first" wristwatch with a liquid crystal display went to another watch, the BWC / Optel LCD wristwatch, which was released in early 1973, about 6 months before the Teletime. The BWC model featured a "dynamic scattering mode" (DSM) display. The early DSM displays worked by applying a high voltage (30 volts) to a thin film of liquid crystals which caused them to align, thereby going from clear to cloudy. DSM LCD displays suffered from low contrast, quality control problems, and poor battery life due to the high voltage required. Due to all of these factors, DSM LCD displays did not last long and were not produced in large numbers.
The Gruen Teletime uses an interesting and uncommon crown and stem based mechanism for setting the time instead of buttons. To set the hours, pull the crown all the way out and turn 45 degrees clockwise. To set the minutes, push the crown in slightly and turn 45 degrees counterclockwise. Push the crown all the way in to exit time setting mode. A few early LCD watches from 1973 to 1974 used stem set mechanisms, which were discontinued and never used again, which is a shame since it's a classy and effective system.
Gruen Teletime Owner's Manual (Click to view)
Case: Very good.
The case is in very good condition with just a few very tiny scratches and nicks visible on the polished bezel. The case back is perfect.
Face / Hands: Excellent.
The face is minty perfect. No marks or signs of aging at all. It looks just like it came from a department store widow in 1973.
Almost perfect with no significant nicks, scratches, or marks.
Band / Bracelet: Excellent.
The original bracelet is minty perfect and complete. The bracelet comfortably fits an 8" wrist.
Function / Accuracy: Excellent.
This watch works perfectly. Digital quartz accuracy.