Japanese enterprises to develop phosphor sheet to enhance the brightness of white LED 10%

Dongli has developed a white LED device can improve the brightness of the white devices without increasing the input power. The sheet is made of a phosphor coated with a silicone resin as the main ingredient, and is used for the combination of a blue LED and a yellow phosphor or a red green phosphor.

Since the sheet can improve the brightness, the utility model is applied to the high-power lighting. Improve the brightness is conducive to reducing the number of LED devices and reduce the input power, help to reduce the weight of the car headlights and energy saving. Pure electric vehicles need to extend the distance of a single charge can be driven, while the headlights to achieve energy saving is conducive to extend the distance. In addition, the sheet can also reduce the use amount of the high phosphor and shorten the manufacturing process, thereby reducing the manufacturing cost.

The sheet to improve brightness white LED device is realized through the following two points: 1) that the refraction of silicone resin as the adhesive rate close to the refractive phosphor material - Gan LED chip rate (2.5); 2) phosphor particle size increases.

In other words, in the blue LED and phosphor composed of white LED devices, the LED chip light through the spread of fluorescent adhesive will change color. It is annoying that the refractive index of the LED chip is different from the refractive index of the coated phosphor. Therefore, some of the light emitted from the LED chip is wasted at the interface between the chip and the adhesive.

(1) in order to reduce the amount of light wasted due to total reflection. By increasing the refractive index of the adhesive, the refractive index of the adhesive is close to the refractive index of the chip, thereby reducing the total reflection of light. According to Dongli, the refractive index of ordinary silicone is 1.5. The development of the adhesive is 1.6. It points out that this increases the amount of available light by 10%.

(2) the use of the "phosphor particle size is greater, the brighter the light" principle. The average particle size was increased by 10 mu ~ 15 m by mixing the phosphor with larger particle size than before. If you simply increase the particle size of the phosphor can be done before. Previously did not do so, because the larger the particle size of the phosphor, the phosphor in the adhesive, the more serious the precipitation and agglomeration of phosphor. To this end, Dongli has developed a technology to make the phosphor particles more evenly dispersed. In this way, the particle size of the phosphor can be reduced, even when the large particle size phosphor is dispersed. In addition, the uniform distribution can also reduce the white light color difference.

The newly developed phosphor sheet also establishes a technique for the high concentration of phosphor in the binder. Thus, the phosphor sheet can be thinned to 30 m, and the heat dissipation performance can be improved. In the need for higher brightness in the use of the need to increase the input power to ensure that the brightness, the heat dissipation of the sheet is high, can be used directly.

When the sheet is heated to about 80 degrees Celsius, it will show adhesion. Therefore, when the sheet is laminated onto the chip, no adhesive is required. Moreover, unlike the original pouring liquid in the silicone resin and the method of spraying the liquid by the sprayer, the fluorescent layer can be formed on the light-emitting surface of the LED chip. In this way, can make high phosphor (about 1 million ~ 2 million yen /kg) dosage than traditional technology to reduce the amount of 2 ~ 3, and sometimes even can be reduced by. In addition, you can significantly shorten the traditional method requires 3 to 5 hours of white LED after the process (using the wafer chip manufacturing process of LED devices) time. Dongli said it would halve the total cost of white LED devices.

In addition, according to the introduction of Dongli, in the past can not increase the input power under the premise of the brightness of more than 10% of the phosphor sheet. Also, there is no phosphor sheet, which does not require adhesive when heated. The company will take advantage of these two characteristics to seize market share. Sheet was started in January 2015 sales and production. Initial production of 10 thousand / month. Dongli said it would reach as soon as 100 thousand / month".

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