Self-powered lighting

I had find many products about Key Chain Watch from some websites such as

	LED Key Chain Lights Specifications: 1) Anodized brass construction 2) Using 4 x AG3 batteries LED Key Chain Lights mo
	Fancy Pens (Stretchy Pen with Plastic.. 1)material: environment-friendly Vinyl; 2)size: approx. 5.5 cm; 3)colorful stretcy pen inside;..

And you can see more from countdown clock keychain wholesale tiffany keychain wholesale digital keychain ultimate christmas present static discharger keychain wholesale shackle keychain digital pictures keychain ledlaser pointer keychain wholesale chanel keyrings

Radioluminescent 1.2 Curie 4" x .2" Tritium vials are simply tritium gas filled thin glass vials whose inner surface are coated with a phosphor. The "gaseous tritium light source" vial shown here is 1.5 years old.
Self-powered lighting is a generic term describing devices that emit light continuously without an external power source. Self-powered lighting is most frequently used on wristwatches (i.e. Night watches), gun sights, and certain emergency and tactical equipment.
Early self-powered lighting used radium paint, which posed serious health risks to the workers who processed and applied it as well as to the users of devices incorporating it. Gaseous tritium, a radioactive isotope of hydrogen, has also been used in self-powered lighting applications, such as emergency exit signs. More recently, many applications using radioactive materials have been replaced with photoluminescent materials.
Contents
1 Tritium lighting
1.1 Self-luminous microspheres
1.2 Physics behind the light
2 Uses of self-powered lighting
2.1 Small arms sights
3 Legal issues
4 Health concerns
5 References
6 External links
7 See also
//
Tritium lighting

Radioluminescent keychains
Tritium lighting is made using glass tubes with a phosphor layer in them and tritium (a hydrogen isotope) gas inside the tube. Such a tube is known as a "gaseous tritium light source" (GTLS), or beta light, (since the tritium undergoes beta decay).
Self-luminous microspheres
A patent application was filed by the US Patent Office in 2007 for sand-grain-sized tritium containers or glass or polymer "microspheres" that can be applied in self-powered lighting paint.[1]
The patent application states that the plurality of individual containment microspheres minimizes the escape of radioactive gas in the event of any physical damage to an assembly of such microspheres. It also states that the radioactive gas has a relatively large contact surface with the phosphor particles, thus causing a relatively efficient light emission from the surface of the particles.[2][3]
Physics behind the light
The tritium in a gaseous tritium light source undergoes beta decay, releasing electrons which cause the phosphor layer to fluoresce.
During manufacture, a length of borosilicate glass tube which has had the inside surface coated with a phosphor-containing compound is filled with the radioactive tritium. The tube is then fused with a CO2 laser at the desired length. Borosilicate is preferred because it is a type of glass noted for its strength and resistance to breakage. In the tube, the tritium gives off a steady stream of electrons due to beta decay. These particles excite the phosphor, causing it to emit a low, steady glow. One could use any beta particle-emitting substance, but in practice tritium is preferred because it is not very hazardous.
Various preparations of the phosphor compound can be used to produce different colors of light. Some of the colors that have been manufactured in addition to the common phosphorus green are red, blue, yellow, purple, and orange.
The types of GTLS used in watches give off a small amount of light姊無t enough to be seen in daylight, but enough to be visible in the dark from a distance of several meters[citation needed]. The average such GTLS has a useful life of 1020 years. As the tritium component of the lighting is often more expensive than the rest of the watch itself, manufacturers try to use as little as possible. Being an unstable isotope with a half-life of about 12.36 years, tritium loses half its brightness in that period. The more tritium that is initially placed in the tube, the brighter it is to begin with, and the longer its useful life. Tritium exit signs usually come in three brightness levels guaranteed for 10, 15, or 20 year useful life expectancies[citation needed]. The difference between the signs is how much tritium the manufacturer installs.
Uses of self-powered lighting

A "permanent" illumination watch face
These light sources are most often seen as "permanent" illumination for the hands of wristwatches intended for diving, nighttime, or tactical use. They are additionally used in glowing novelty keychains and in self-illuminated exit signs. They are also favored by the military for critical applications where illumination of the glow-in-the-dark sort is desired but a power source may not be available. Some uses of this sort are analog dials in aircraft, in compasses, and sights for weapons. They were invented in the 1960s as a reliable self-powered light source for NATO[citation needed].
Tritium lights are also found in many old rotary dial telephones, though due to their age they no longer produce any useful amount of light[citation needed].
Small arms sights
Tritium is used to make the...(and so on)

	Key Chain Watch Fashionable Key Chain Watch, Japan Movement Key Chain Wat

You can also see some feature products :

corporate items keychains photo changeable keychain discount tiffany keychain crystal engraved keychain photo insertable keychain coach keyring;a/f keyring photo projection keychain wholesale silver keychain upscale sculpture present handbags wallets keychain sterling silver keychains personalized crystal keychain cross keyholdermetal keychain louis vuittion keychain digitl picture keychain promotion pvc keychains replica hermes keyrings discount solar keychain replica chanel keyrings solar prowered keychain shopping coins keychain