The most common type of watch is the wristwatch, worn on the wrist and fastened with a watchband made of leather, nylon or other plastics (then called strap), metal links (called bracelet) or even ceramic. Before the inexpensive miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried separately, often in a pocket and attached to a watch chain or watch fob.
In the 21st century, technological advances in metallurgy, composite materials development and physical vapor deposition greatly influence watch design and manufacturing. Solid stainless steel, titanium, tungsten carbide, carbon fiber, high-tech ceramic and ion plating processes dominate a considerable market share of today's modern watch-making industry. Sapphire crystals are often incorporated to complement and enhance the durability of a quality watch.
Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements. The some watches have radio-controlled movements that are miniaturized, portable versions of radio clocks. Expensive, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping, often have purely mechanical movements and are powered by springs, even though mechanical movements are less accurate than more affordable quartz movements.
Pocket timepieces
Main article: Pocket watch
In the 15th century, navigation and mapping increased the desire for portability in timekeeping. The latitude could be measured by looking at the stars, but the only way a ship could measure its longitude was by comparing the midday (high noon) time of the local longitude to that of a European meridian (usually Paris or Greenwich)—a time kept on a shipboard clock. However, the process was notoriously unreliable until the introduction of John Harrison's marine chronometer. For that reason, most maps from the 15th century through the 19th century have precise latitudes but distorted longitudes.
The first reasonably accurate mechanical clocks measured time with simple weighted pendulums, which are unworkable when irregular movement of the fulcrum occur whether at sea or in watches. The invention of a spring mechanism was crucial for portable clocks. In Tudor England, the development of "pocket-clockes" was enabled by the development of reliable springs and escapement mechanisms, which allowed clockmakers to compress a timekeeping device into a small, portable compartment.
In 1524, Peter Henlein created the first pocket watch.[1] It is rumored that Henry VIII (the portrait of Henry VIII at this link shows the medallion thought to be the back of his watch) had a pocket clock which he kept on a chain around his neck. However, these watches only had an hour hand—a minute hand would have been useless because of the inaccuracy of the watch mechanism. Eventually, miniaturization of these spring-based designs allowed for accurate portable timepieces (marine chronometers) which worked well even at sea.
In 1850, Aaron Lufkin Dennison founded Waltham Watch Company, which was the pioneer of the industrial manufacturing of pocket watches with interchangeable parts, the American System of Watch Manufacturing.
Breguet developed the first self-winding watch known as the perpetual in 1780
Parts
The first two are key mechanisms within any mechanical watch of classical design; the third is optional:
The escapement – a mechanism that controls and limits the unwinding of the watch, converting what would otherwise be a simple unwinding, into a controlled and periodic energy release. The escapement does this by interlocking with a gear in a simple manner that switches between a "driven" and a "free" state, with abrupt locking at each end of the cycle. The escapement also for the same reason produces the ticking noise characteristic of mechanical watches.
The balance wheel together with the balance spring(also known as Hairspring) – these form a simple harmonic oscillator, which controls the motion of the gear system of the watch in a manner analogous to the pendulum of a pendulum clock. This is possible because the moment of inertia of the balance wheel is fixed, and the wheel as a whole provides a regular motion of known period.
The tourbillon – a rotating frame for the escapement. It is intended to cancel out or reduce the effects of bias to the timekeeping of gravitational origin, which might result from the watch being kept in a particular position for much of the day. It is technically very challenging to create a high quality tourbillon, and those made by specialists and found in prestige watches are often very highly valued.
NB: The pin-lever (also called Rosskopf) movement, as per the name of its inventor: Georges Frederic Roskopf: This cheaper version of the fully levered movement had been manufactured in huge quanties by many Swiss Manufacturers as well as Timex, has been replaced by Quartz movements
Watch movements
A movement in watchmaking is the mechanism that measures the passage of time and displays the current time (and possibly other information including date, month and day). Movements may be entirely mechanical, entirely electronic (potentially with no moving parts), or a blend of the two. Most watches intended mainly for timekeeping today have electronic movements, with mechanical hands on the face of the watch indicating the time.
Purely mechanical watches are still popular. The high level of craftsmanship of purely mechanical watches accounts for much of their attraction. Compared to electronic movements, mechanical watches are inaccurate, often with errors of seconds per day. They are frequently sensitive to position and temperature, they are costly to produce, they require regular maintenance and adjustment, and they are more prone to failure.
Generally speaking, inexpensive and moderately priced timepieces with electronic movements now provide most users with timekeeping more accurate than the most expensive Rolex or Patek Phillipe. The most expensive, diamond encrusted Rolex contains a similar movement as its less expensive C.O.S.C rated brethren and all modern models can keep time to within 1 second a day. However, in recent times there has been less emphasis on one's watch for time precision as many people now carry multiple devices that will tell them the time accurately such as mobile phones, PDAs and laptops, these finely crafted mechanical watches have remained popular as precision time pieces and in many cases more so because of their aesthetic value as jewellery.
Digital display
Datalink USB Dress edition with Invasion video game, (one of eighteen posible modes). (Three lives remaining). The display is dot matrix. The watch crown (icontrol) can be used to move the defender left to right and the fire control is the Start/Split button on the lower side of face of the watch at 6 o' clock. The pixels of the invaders appear slightly blurred upon picture magnification because of the animation of the aliens. The faint pixels diagonally to the left of the defender block are pixel traces of alien missiles. This Datalink model is waterproof to 30 m.
Since the advent of electronic watches that incorporate small computers, digital displays have also been available. A digital display simply shows the time as a number, e.g., 12:40 AM instead of a short hand pointing towards the number 12 and a long hand pointing towards the number 8 on a dial. Some watches, such as the Timex Datalink USB, feature dot matrix displays.
The first digital watch, a Pulsar prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data. John Bergey, the head of Hamilton's Pulsar division, said that he was inspired to make a digital timepiece by the then-futuristic digital clock that Hamilton themselves made for the 1968 science fiction film 2001: A Space Odyssey. On April 4, 1972 the Pulsar was finally ready, made in 18-carat gold and sold for $2,100 at retail. It had a red light-emitting diode (LED) display. Another early digital watch innovator, Roger Riehl's Synchronar Mark 1, provided an LED display and used solar cells to power the internal nicad batteries.[8] Most watches with LED displays required that the user press a button to see the time displayed for a few seconds, because LEDs used so much power that they could not be kept operating continuously. Watches with LED displays were popular for the next few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power. The first LCD watch with a six-digit LCD was the 1973 Seiko 06LC, although various forms of early LCD watches with a four-digit display were marketed as early as 1972 including the 1972 Gruen Teletime LCD Watch, and the Cox Electronic Systems Quarza.
Digital watches were very expensive and out of reach to the common consumer up until 1975, when Texas Instruments started to mass produce LED watches inside a plastic case. These watches, which first retailed for only $20, and then $10 in 1976, saw Pulsar lose $6 million and the brand sold to competitors twice in only a year, eventually becoming a subsidiary of Seiko and going back to making only analogue quartz watches.
From the 1980s onward, technology in digital watches vastly improved. In 1982 Seiko produced a watch with a small TV screen built in and Casio produced a digital watch with a thermometer and another watch that could translate 1,500 Japanese words into English. In 1985, Casio produced the CFX-400 scientific calculator watch. In 1987 Casio produced a watch that could dial your telephone number and Citizen revealed one that would react to your voice. In 1995 Timex release a watch which allowed the wearer to download and store data from a computer to their wrist. Since their apex during the late 1980s to mid 1990s high technology fad, digital watches have mostly devolved into a simpler, less expensive basic time piece with little variety between models.
Despite these many advances, almost all watches with digital displays today are not considered an impressive form of jewelry and most are seen as being in the category of simple timekeeping watches.
Expensive watches for collectors rarely have digital displays since there is little demand for them. Less craftsmanship is required to make a digital watch face and most collectors find that analog dials (especially with complications) vary in quality more than digital dials due to the details and finishing of the parts that make up the dial (thus making the differences between a cheap and expensive watch more evident).
