Turin – Italy

Collection of Quartz Wrist Watches – Progress in precise timekeeping.

 

During my whole life the precise timekeeping was my favorite field of interest. Already two years before my studies in electronic engineering I built my first eletronic table clock. It had a 100kHz quartz crystal oscillator made with germanium transistors coming from a telecommunication standard. The divider down to 50Hz was made with 4 flip-flops per decade of division, all made with germanium transistors, discrete resistors and capacitors. The signal of the last flip-flop went to a push-pull amplifier which drove a 50Hz synchrone motor with a step-down gear for the time indicating hands.

During my studies I built in 1966 a second table clock indicating the 1/10 and 1/100 of a second with two vertical bargraphs, each made of 10 smal discharge lamps. Seconds, minutes and hours were displayed conventionally with hands. The reference was an oven stabilized 100kHz crystal.

Also my final work in oder to become a graduated engineer handeled with crystal oscillators.

My first job after the exam of electronic engineer in 1968 was at the Centre Electronique Horloger (CEH) in Neuchatel Switzerland where we worked on the design and industrialisation of the first quartz wrist watch, the Beta 2 and 21.

The shareholders of the CEH, founded in the early 60-ies, were the major Swiss Watch manufacturers. They wanted to have a common organisation to compete the japanese which were always more often winning the annual timekeeping contest at the swiss observatory.

My work at the CEH consisted in the improvement of the crystal suspension in order to make it more shock resitent. Residual frequency changes after a shock had to be, translated in timing errors, less 1/100 sec/day. The residual errors happened when the crystal, at a shock, was touching it’s enclosure or when an irreversible deformation of the SnPbAg solder points on the crystal and at the attack points of the suspension wires, at the feedthroughs in the enclosure, happened. The crystal was a “heavy and long” X-Y flexion mode bar (1.2 x 0.8 x 24mm) with a resonance frequency at 8192 Hz. The dimensions were given by the fact that our supplier of the bar could not cut bars of smaler sections. The length at given section, was given by the size of the watch.  A higher frequency would have made the schock sensibility much lower because of the smaller dimensions of the crystal and therfore lower weight. But el. power consumption of the first integrated flip-flop stages made by the CEH increased exponentially with frequency increase, because the flip-flop had very high ohmic (meg Ohms) collector resistors and therefore high parasitic capacitors, which had to be, with every state change of the flip-flop, charged and discharged.

For the suspension of the crystal 4 round phosphorbronze wires were soldered with a SnPbAg solder, at that time the used manner for low frequency crystals. The wires were about S-form bended and soldered to the crystal at the nodal points. I changed the section of the wires into a rectangular one (proportion about 1:5) and used copperberylium instead of phosphorbronze and used as solder an Au-eutectic, which is much more elastic in the physical sense (small deformations are not residual) compaired with PbSnAg solder. These modifications increased the quality factor of the resonator by more than 2 times and the acceleration resistance by a factor of about 10.

Also the enclosure of the crystal had to be changed for mass production. It was decided already before my arrival at the CEH to use an electric discharge welding with pressure under vacuum. I would have prefered to search for a cold weld solution, which was successfully experimented in the US for high frequency precision crystals. But time was a critical issue because of the Japanese (Seiko) competition. The electric welding was not successful because of leakage or fused metal sparkling on the crystal. The solution used for the first production unit was a mix  of the prototype units and  electrical welding. The vacuum inside the enclosure was made with in the housing soldered cupper (OFC) tube which was closed by pressing the tubewalls together (cold welding), same as already made for the prototypes.

In my opinion the swiss watch industry, which was very rich at that time, never belived at that time to be in the near future, about within 10 years, compeled to produce electronic wrist watches for survival. Many were active in electronics, but not for wrist watches but for time measuring at sport competitions like Omega and Longines or building table clocks (marine cronometers) for the time keeping contests at the observatories. All these activities were for image reasons of the company or for publicity.

It was unique that a joint company, the CEH, was designing (prototypes were presented 1967) and industrializing (industrially produced series presented 1970) a watch caliber equal for all share holders, which were in the market hard competitors.

A production of 6000 pcs was sheduled. The main modules of the movement were the quartz resonator made by Oscilloquartz, the vibration motor (256Hz) made at Omega and the IC made at the beginning at the CEH, later at Faselec and at a newly created company at Marin. The movements were assembled in 4(?) places formed by one or more share holders, one was Omega. Every shareholder had to order a number of movements according its needs and pay for them. The shareholders put these movements into their individual cases with the own logo and individual names for the watch, but the watch movement was for all the same, the Beta 21. All used at the beginning very heavy gold cases with gold bracelets. The salesprices were about 12k sFr or more in order to limit sales because not enough movements were available in the first years.

 

Some big swiss watch companies and associations of smaller companies made at the same time, indipendent of the CEH-design, their own or additional designs of quartz wrist watches, even when beeing share holders of the CEH.

So did Omega which made with the Battelle institute in Geneva a contract for a high precision quartz wrist watch – the Megaquartz 2.4 MHz – some prototypes were presented to the public in 1970 at the Basle Fair. It was so precise that it was sold, as an option, with the observatory certification of Marine Chronometer.

Also Longines presented in 1970 its Ultraquartz designed by Longines in collaboration with Golay Lausanne, for the electronic analog frequency divider, made with discrete micro components soldered by hand .

Very remarkable for the early design of current controlled dividers, was the design of the AFIF, a department of the Swiss technical high school at Zurich, which was, for to the author unknown reasons, never produced in series, but some prototypes were  presented with the name Neosonic at the Basle Fair in 1970. The AFIF had a design contract with Rolex, Roamer and other smal Swiss watch manufactures.

Some other companies made direct collaborations with the major semiconducter manufacturers as Girard-Perregaux with Motorola. The result was the caliber GP350 presented 1972 at the Basle Fair.

All major semiconductor manufacturers were very active at that time with the design of low power and low supply voltage frequency dividers because they saw the immense market for wrist watches. Motorola offered to the manufacturers a complete kit consisting in IC, stepping motor and crystal, they even designed an instrument to adjust the watch. But they were only partially successful because the watch manufacturers asked for exclusivity without having the numbers needed by the semiconducture manufacturer for low price.

The 70ies was the decade during which every year the number of innovations increased from year to year. New solutions to show time using LED and/or LCD, thinner and smaller watches, lower price, additional features incorporated like calculator. All this was made possible with the progress in semiconductor manufacturing and new technology to produce the crystal resonator – the lithografically made quartz tuning- fork with 32kHz. The tuning-fork is also much more shock resistant, because hold at one side in a fixed manner, which made the watches more reliable but not more accurate.  More accuracy was a by the market, less asked issue, because an error of 1 minute per year was accepted, mainly because of the in any case needed setting changes winter-summer time.

 

Concerning permanent accuracy no big innovations happened up to 1990 when Junghans presented its radio controlled wrist watch Mega 1 with a LCD display, an year later the version with hands for minutes and hours was presented. It received the time coded radio signal transmitted by DCF close to Frankfurt at 77,5 kHz and corrects with this signal the internal quartz crystal time base. When the DCF-signal is absent, for maintenance work on the transmitter or because the watch is too far from the transmitter, more than about 1500km, the watch runs controlled by its own time base, which has an accuracy as a normal quartz watch. The watch therefore runs with an error of some seconds, if the absence of the transmitter signal had a duration of several weeks or months. When the transmitter signal returns, the watch corrects its accumulated error. In the Mega 1 with all LCD this was simply done by resetting the whole display and setting it according the coded time information of the transmitter. But in the version with hands this was less trivial. The watch had to know the position of  the hands. This was done with a small hole in the minute and hours wheels and a light beam emitted by the electronics and received by it, by double deviation at the bottomcover of the watch. The wheels were fast stepped forewards until the light could pass through all the holes in order to be received, which was the position known by the watch, then the hands were again fastly moved to the correct time position.

For many years I weared such a watch with much satisfaction. The only missing feature was the knowledge if an eventually needed correction was done or not, without compairing the watch with another accurate time keeper. This feature is mainly needed when the watch is far from the transmitter where the signal is not received regularly.

This feature was included in the radio controlled wrist watch of Citizen Eco – Drive. Pressing a push-button on the watch, the seconds hand moves fast in a position where it shows with its back if the radiosignal has been received in the last 24 hours and with which strength. Also this watch makes time corrections in a limited distance from the transmitter DCF, but it is available for receiving other time transmitting radio stations as MSF in UK and others.

The most sofisticated watch, only timekeeper, was made available in 2012 in a limited edition of 1000pcs –  the Citizen “H990” Eco-Drive Satellite Wave. It receives the signal of the navigation system GPS, which is received world wide. The watch takes the energy to work from the environment light with fotocells. The description how it works, is omitted in the 74 pages of the manual. At the moment I do not open mine, because it is still in warranty. To make a receiver for such a high frequency – 1.7 GHz – and with such a low power consumption is a technical masterly achievement. The task to show correct time with the GPS-signal has the complication that GPS is not transmitting directly the whole coded time information, but only the seconds pulse. The time has to be calculated by the watch with the data of the calculated position of the watch.

The H990 is quite big, like an antique pocket watch, about 50 mm in diameter without pushbuttoms and 20 mm thick, but at the moment big wrist watches are in fashion. A direct view of the satellite is needed to receive its signal, because such short waves, as the GPS signal are, do not pass through walls etc. In order to run in absence of GPS signal it has, as all quartz watches, a quartz resonator inside. The one owned by me makes a timing error without correction of about 2 seconds per month, which is well according specification of +/- 15 sec per month. To correct this error I have to be outside with sunshine, far from trees and bouldings and holding the watch with the dial oriented to the sky, pushing for more than 3 seconds a button, continue to hold it firmly until I see that the seconds hand moves normally. Pushing the same button for less than 3 seconds I can see if a correction happened in the last 24 hours.

Also Seiko has such a GPS-watch, called Astron, which seems to be very similar to the Citizen, but I have never seen one.

All the fotos hereafter shown are of watches owned by the author

 

Additional informations for:

Beta21 in the book:

“L’aventure de la montre à quartz” written by Max Forrer, Henri Oguet, René Le Coultre, André Beyner  ISBN 2-88380-016-2

 

Beta 21 and Megaquartz in the book:

“OMEGA SAGA” ISBN 2-88380-010-3

 

Persons which were active in the design of early quartz wrist watches in the book:

“Kinder der Quarzrevolution” written by Lucien F.Trueb  ISBN 978-2-940088-25-6

 

Informations of nearly all manufacturers worldwide of quartz wrist watches:

web site:doensen.home.xs4all.nl