High-voltage(AC) LED lens(Ⅲ)

Views: Date：2012/8/8

3.AC LED
Energy efficient, green, long-life characteristics of the emerging LED lighting technology is developing rapidly, and application of new technologies, new programs have emerged. LED lighting design can be combined with the light source characteristics, such as the light source point, cold light, and color change, will become the mainstream lighting market. In recent years, with the LED grain process, package architecture design, technology and other aspects of continuous improvement in the material selection, a new kind of AC diode (AC LED) technology emerged, by a new idea to promote the LED lighting technology, practical use.

The traditional LED is a typical low-voltage DC devices can not be directly used in our daily lighting power high-voltage AC (AC 100 ~ 220V), power step-down must be high pressure, or a switch, then current (AC) to transform into DC (DC), and then converted into DC current source, in order for the LED light source.

LED lamps will inevitably have a certain space to accommodate the converter is not conducive to lighting design and miniaturization. Systems through the transformation aspects of energy must have a certain amount of loss, about 15% to 30% of the conversion of the DC LED between AC, DC power has been damaged, the efficiency of the system difficult to achieve 90% conversion device of the existence of The higher cost of LED lighting products, has also become a bottleneck restricting the product life of the LED light source, can not reflect the characteristics of the LED longevity people.

The AC LED as opposed to traditional DC LED without through the AC / DC conversion can directly plug in 220V (or 110V) AC LED lighting technology, the key technology of AC LED light source is LED die in the package special combinations of technology, while taking advantage of the LED PN junction diode characteristics doubles as a rectifier, more grain through the semiconductor production process on a single chip, high-power single-grain (SINGLE POWER CHIP), and a staggered matrix The arrangement process to form a bridge circuit, the AC current can double the wizard through to achieve luminous.

AC LED mature products such as Seoul for AC110V the AX3201, AX3211 (http://www.optic-fov.com/en/products/505.html) and for 220V, AX3221, AX3231 (http://www.optic-fov.com/en/products/504.html) for AC110V power 3.3W ~ 4W, operating current of 40mA; for AC220V power 3.3W ~ 4W, the operating current of 20mA LED die directly encapsulated in copper and aluminum substrates .

AC LED has just started, at this stage there are two shortcomings First, the luminous efficiency and high DC LED. Second, the AC LED has a risk of electric shock. AC LED directly connected to high voltage power grid. If using metal fins heat, prone to risk of electric shock, the need to study the indirect cooling solutions, such as liquid-filled solid-state LED lighting.

AC LED brightness, power is not ideal, but the simple application of the AC LED, no transformer converter and constant current source, and low-cost, High-rate show a strong vitality. AC LED technology in the rapid development can be envisaged in the near future, high brightness, high power, low-cost products will be a large number of available, greener, more environmentally friendly for our world bright.

4.THE DEVELOPMENT OF NEW PHOSPHORS
YAG: Ce3 + is the first widely used in a phosphor white LED technology, but because of its less red component because of its light-emitting spectrum, it is difficult to obtain high color rendering index and a low color temperature of white light LED, on the other hand, continuing to promote the development of semiconductor lighting phosphors have been developed to a higher conversion efficiency. Early days of YAG: Ce3 + join of (Ca, Sr) S: of Eu2 +, (Ca, Sr) Ga2S4: Eu2 + red and green phosphors to achieve high color rendering index, low color temperature requirements, but due to this type of alkaline earth metal sulfide physical and chemical properties of instability, deliquescence, volatile and corrosive and other issues. Can not meet the demand for LED lighting industry. Recently, it has developed a thermal stability and excellent chemical stability of the red phosphor, high color rendering index, low color Wen Baiguang LED can completely replace the alkaline earth metal sulfides, because of its tetrahedral structure of silicon-nitrogen (oxygen), known as nitrogen oxides, has a higher excitation efficiency.