The quartz watch

Its construction is merely a matter of miniaturising quartz clocks or chronometers. Simple enough in principle but the quartz, circuit and motor are difficult to miniaturise. What's more, the energy balance does not apply to watches. Quartz is well known as a highly stable resonator and is therefore very promising for the future. On account of its piezoelectric effect, the electromechanical transducer is contained in its very substance. The quartz used in the earliest developments was a type of bending bar with the same length as the diameter of a normal watch. Its short history as a watch component would include one or two reductions in size and then two important steps. Firstly, quartz took the form of a tuning fork, thereby greatly reducing its size. A new machining method then led to a reduction in its cost price.

Meanwhile, the integrated circuit appeared in electronics. This made it possible to integrate and connect these components with one another on a small silicon chip. It was a huge step towards miniaturisation. It is worth noting that a quartz watch with discrete electronic components did in fact exist. It was an interesting development but had no future when matched against the scope offered by integrated circuits.

'The quartz watch adventure'

An exhibition devoted to quartz watches was hosted until 20 October 2002 by the Musée international d'horlogerie (MIH) in La Chaux-de-Fonds. The exhibition was staged in conjunction with the launch of a book whose four authors were witnesses to events at the time. 

The rectangular Beta 2 quartz watch won the Neuchâtel Observatory chronometry competition in 1967. It was an improved version of a prototype developed in 1963 at the Centre électronique horloger (CEH), founded in 1962. The industrial version of the Beta 21 was marketed in 1970. 

Subsequently dissolved in 1998, the CEH was the forebear of the Swiss Centre for Electronics and Microtechnology (Centre suisse d'électronique et de micro-technique or CSEM), set up in Neuchâtel in 1984. Former staff at the Institute, Max Forrer, André Beyner, André Le Coultre and Henri Oguey, look back on the highlights of their experiences in their work, 'The quartz watch adventure'.

Ten quartz prototypes - six Beta 2 watches and four watches produced by the Japanese firm Seiko - were entered in the 1967 Observatory competition. The Beta 2 watches from the CEH won the top six places in the competition, followed by the Japanese watches.

Eliminating the balance

In a quartz watch, the balance and spring assembly of a mechanical watch, with its to-and-fro vibrations, is replaced with a quartz crystal coupled to an oscillator. The trick lies in reducing the frequency of vibration of the quartz atom to one to-and-fro movement per second.

This operation is achieved through an integrated electronic circuit. The frequency of vibration of the quartz in a Beta 2 watch was 8,192 movements per second (8,192 Hertz). Thanks to the miniaturisation of components, today's watches operate at a frequency of 32,768 Hertz.

First integrated circuit

This frequency corresponds to 2 to the power of 15, which means that the integrated circuit halves the initial vibration 15 times in order to achieve one pulse per second. The appearance of the 1 Hertz signal triggers a vibration in the motor driving the watch hands.

The high frequencies have the advantage of being divisible to approximate the length of the astronomical second. The marketed version of the Beta watch incorporated an integrated circuit measuring 2 millimetres from side to side. The movement was priced at 700 francs whereas it costs less than one franc today.

Japanese quicker off the blocks

The Japanese brought out their watches earlier than the Swiss watch industry. The Seiko 35SQ was rolled out in 1969. Japanese industry focused on the low-end electronic watch. It rapidly supplanted its mechanical counterpart in the same category, catapulting the "Jura Arc" into a watchmaking crisis.

After lagging behind the Japanese for a while, the Swiss watch industry fought back in 1982 with the creation of Swatch. This mass-market electronic watch comprised a minimum of components and a high percentage of plastics. It has since beaten every sales record.

How it works

These days, two technologies are concurrently employed by the Swiss watch industry: on the one hand, electronic technology with the analogue electronic quartz watch (sometimes combined with digital display) and, on the other hand, the more traditional technology of the mechanical watch. Electronic items - predominantly analogue - account for almost 90% of all Swiss watch manufacturing output in terms of volume, while mechanical items, which account for 10%, are key insofar as they alone represent over 52% of total export value.

Quartz watch 

The heart of a quartz watch consists of an integrated circuit made from a large number of electronic components sharing a few square millimetres of space. The energy source is provided by a miniature battery with a lifespan of several years. The time is divided by a quartz oscillator which is caused to vibrate by the energy supplied by the battery. Quartz watches are extremely accurate thanks to their high frequency of vibrations (32 kHz); their annual variation is only about one minute per year, which amounts to less than a second a day. Two main types of product are distinguishable: 1) analogue display watches (hands), 2) digital display watches fitted with liquid crystals which receive, directly from the integrated circuit, the pulses needed to display the time. There is therefore no mechanical transmission. These two types of display are sometimes combined in the one watch (double display) as a useful means of telling the time and, for example, measuring short intervals of time. 

Electronic quartz watch  1)  Battery providing the power 2)  Integrated circuit powered by the quartz and controlling the pulses to the stepping motor 3)  Quartz dividing the time 4)  Trimmer regulating the frequency 5)  Stepping motor transforming the electrical pulses into mechanical power 6)  Gear train activating the hours, minutes, seconds hands 7)  Analogue display

The traditional mechanical watch is made up of about 130 pieces assembled in three main parts, namely the energy source, the regulating parts and the display. The number of component parts is much higher in complicated watches (date, moon phases, fly-back hand, etc.). The "ébauche" (about 60 pieces) is fitted with the regulating parts and a number of other components and forms the movement, i.e. the internal mechanism of the watch, making it possible to maintain constant tension in the spring once it has been wound manually or automatically (by movements of the wrist) and to adjust the display using the hours, minutes and seconds hands. A watch is said to be finished when the movement has been fitted with its exterior (case, dial, hands). 1)  Mainspring providing the power 2)  Gear train transmitting the power 3)  Escapement distributing the pulses 4)  Oscillating balance dividing the time 5a) Winding stem for manual winding and setting 5b) Rotor for automatic winding 6)  Analogue display Automatic quartz watch. The combination of these two technologies recently gave rise to a new type of watch movement which has the features of a quartz movement along with those of a self-winding mechanical movement (automatic watch with quartz precision). The principle on which it operates is simple yet revolutionary: an automatic winding mechanism (oscillating weight) stretches the mainspring which, when it relaxes, triggers a micro-generator that converts the mechanical energy into electrical power. This power is then accumulated in a capacitor. The system the works like a traditional quartz watch, i.e. the integrated circuit controls the power supply and delivers the pulses needed to drive the stepping motor.