Due to its small size, low cost, and simple control loop design, the blue-ray chip + YAG aluminate yellow phosphor is currently the mainstream implementation method of white LEDs, and it has also become the way most LED packaging manufacturers in China follow. However, the white LED packaging patent of YAG yellow phosphor is owned by Nichia Chemical. White LED products used by Chinese manufacturers using this technology are bound to be contained by the patent when they are exported, which will drag down the market. Therefore, to circumvent the international patent blockade of blue LED+yellow phosphors, breakthroughs must be made on key materials.
The principle of the blue LED+YAG phosphor is to coat a YAG phosphor on a blue chip with a wavelength of 460 nm, and to excite the phosphor with a blue LED to generate a 555 nm wavelength yellow light complementary to blue light, and the complementary yellow light and blue light are mixed to obtain white light. It is unrealistic to achieve breakthroughs in chip manufacturing/epitaxy materials in the short term. The industry generally agrees that new phosphor materials are an effective way to break through the international patent barriers of white LEDs. For example, Osram's TAG aluminate yellow phosphor is a successful example of breakthrough YAG phosphor patent (other major phosphor technologies used to realize white LEDs, Toyota Synthetic, Inter-American, and TridONic's silicate series phosphors, etc.) . The yellow powder on the current Chinese market is almost all of YAG's patented YAG aluminate phosphors, so it is necessary to take the initiative in the white LED market. China needs its own proprietary white LED phosphor technology. Dr. Wang Haijun from UCI Core Optical Corp. told EE Times that the nitride yellow phosphor is expected to replace the YAG aluminate phosphor to circumvent Japan’s chemical-related patent barriers.
Phosphors are one of the key materials that affect the efficacy, lifetime, color rendering index, and color temperature of white LEDs. Uneven color brightness is mainly caused by uneven coverage of the phosphor outside the chip's light-emitting layer. Therefore, how to make the phosphor cover the outside of the chip light-emitting layer is the focus of the white LED package, and the uniformity of mixing of the phosphor and the packaging material is more uniform. It will affect the consistency of the white light emitted by the LED. The disadvantage of the blue LED chip with YAG yellow phosphor is that the red spectrum has poor brightness and color. It is reported that Ulead’s nitride yellow phosphor won the “South China Sea Cup†national semiconductor lighting product innovation award in 2010. The reason for the award is that the nitride yellow phosphor can have higher color rendering than YAG aluminate and silicate phosphors. Sex and cover a higher color gamut, suitable for colorful occasions. Wang Hailu said that Ulead's nitride yellow phosphor has been applied for an international patent. Since the red and blue regions of nitride phosphors are relatively large, YAG and silicate can not reach it. At present, its main application is YAG. Markets that cannot be made with powder, such as the company's current high-warming color and plant growth lights in cooperation with the National Academy of Agricultural Sciences, fall into this category. Because different plants have different spectral requirements, in order to achieve the corresponding blue and red light spectrum, a certain percentage of the photon number requirements, if you use the traditional red and blue chips, you need to find the relevant spectral points, easily caused by Uniform problem. The advantage of using phosphors is that red and blue light can be determined according to the number of phosphors, even though the light emitted by 200 LEDs is consistent.
The color gamut refers to the sum of the color that the system can produce. We know that the wider color gamut that the backlight source can achieve, the more vivid the color performance of the LCD. Wang Hailu said that using phosphors to solve the problem of backlight packaging can solve the problem of consistency of light emission. The company's nitride phosphors cover wavelengths from 500nm to 660nm, and LED backlights that many YAG and silicate phosphors cannot achieve. Only nitrides are required. For example, nitride phosphors can achieve YAG and silicates can not achieve pink. In addition, Ulead's core high-power LEDs are mainly used for high color rendering index applications such as photo-filling light and medical machinery shadowless lights. Since the infrared portion of the conventional light source generates heat, it is unfavorable to the patient and its tissue, and the shadowless lamp using a high-color rendering LED includes only visible light and does not generate heat. In high-color applications, product yield can be achieved through color temperature control and other technologies, and its cost will be relatively low. For example, Ulead's high-power LED has only a total deviation of 400k in the 5800k annex of the photographic light plus white zone. The national standard allows the deviation to be in the 1,000k level, and its color temperature requirement is less than half of the national standard deviation. The color temperature drift problem has now been shipped in large quantities.
At the same time, Dr. Wang Haixi stated frankly that the luminous efficiency of YAG phosphors has reached more than 80%, but the efficiency of nitride phosphors is currently relatively low, with a difference of about 10%. However, due to the effect of light efficiency on brightness, general lighting will be more dependent. For applications such as backlighting, higher color rendering and stability are required, and high brightness is not necessarily required. However, because nitrogen oxide phosphors have great potential as emerging phosphor technologies, the development of YAG aluminate can be said to have reached its peak. Therefore, Wang Haixin believes that nitrogen oxide phosphor technology will mature in the next 5-6 years. To upgrade to the current level of YAG, first to break through the monopoly of YAG phosphor patents.
The principle of the blue LED+YAG phosphor is to coat a YAG phosphor on a blue chip with a wavelength of 460 nm, and to excite the phosphor with a blue LED to generate a 555 nm wavelength yellow light complementary to blue light, and the complementary yellow light and blue light are mixed to obtain white light. It is unrealistic to achieve breakthroughs in chip manufacturing/epitaxy materials in the short term. The industry generally agrees that new phosphor materials are an effective way to break through the international patent barriers of white LEDs. For example, Osram's TAG aluminate yellow phosphor is a successful example of breakthrough YAG phosphor patent (other major phosphor technologies used to realize white LEDs, Toyota Synthetic, Inter-American, and TridONic's silicate series phosphors, etc.) . The yellow powder on the current Chinese market is almost all of YAG's patented YAG aluminate phosphors, so it is necessary to take the initiative in the white LED market. China needs its own proprietary white LED phosphor technology. Dr. Wang Haijun from UCI Core Optical Corp. told EE Times that the nitride yellow phosphor is expected to replace the YAG aluminate phosphor to circumvent Japan’s chemical-related patent barriers.
Phosphors are one of the key materials that affect the efficacy, lifetime, color rendering index, and color temperature of white LEDs. Uneven color brightness is mainly caused by uneven coverage of the phosphor outside the chip's light-emitting layer. Therefore, how to make the phosphor cover the outside of the chip light-emitting layer is the focus of the white LED package, and the uniformity of mixing of the phosphor and the packaging material is more uniform. It will affect the consistency of the white light emitted by the LED. The disadvantage of the blue LED chip with YAG yellow phosphor is that the red spectrum has poor brightness and color. It is reported that Ulead’s nitride yellow phosphor won the “South China Sea Cup†national semiconductor lighting product innovation award in 2010. The reason for the award is that the nitride yellow phosphor can have higher color rendering than YAG aluminate and silicate phosphors. Sex and cover a higher color gamut, suitable for colorful occasions. Wang Hailu said that Ulead's nitride yellow phosphor has been applied for an international patent. Since the red and blue regions of nitride phosphors are relatively large, YAG and silicate can not reach it. At present, its main application is YAG. Markets that cannot be made with powder, such as the company's current high-warming color and plant growth lights in cooperation with the National Academy of Agricultural Sciences, fall into this category. Because different plants have different spectral requirements, in order to achieve the corresponding blue and red light spectrum, a certain percentage of the photon number requirements, if you use the traditional red and blue chips, you need to find the relevant spectral points, easily caused by Uniform problem. The advantage of using phosphors is that red and blue light can be determined according to the number of phosphors, even though the light emitted by 200 LEDs is consistent.
The color gamut refers to the sum of the color that the system can produce. We know that the wider color gamut that the backlight source can achieve, the more vivid the color performance of the LCD. Wang Hailu said that using phosphors to solve the problem of backlight packaging can solve the problem of consistency of light emission. The company's nitride phosphors cover wavelengths from 500nm to 660nm, and LED backlights that many YAG and silicate phosphors cannot achieve. Only nitrides are required. For example, nitride phosphors can achieve YAG and silicates can not achieve pink. In addition, Ulead's core high-power LEDs are mainly used for high color rendering index applications such as photo-filling light and medical machinery shadowless lights. Since the infrared portion of the conventional light source generates heat, it is unfavorable to the patient and its tissue, and the shadowless lamp using a high-color rendering LED includes only visible light and does not generate heat. In high-color applications, product yield can be achieved through color temperature control and other technologies, and its cost will be relatively low. For example, Ulead's high-power LED has only a total deviation of 400k in the 5800k annex of the photographic light plus white zone. The national standard allows the deviation to be in the 1,000k level, and its color temperature requirement is less than half of the national standard deviation. The color temperature drift problem has now been shipped in large quantities.
At the same time, Dr. Wang Haixi stated frankly that the luminous efficiency of YAG phosphors has reached more than 80%, but the efficiency of nitride phosphors is currently relatively low, with a difference of about 10%. However, due to the effect of light efficiency on brightness, general lighting will be more dependent. For applications such as backlighting, higher color rendering and stability are required, and high brightness is not necessarily required. However, because nitrogen oxide phosphors have great potential as emerging phosphor technologies, the development of YAG aluminate can be said to have reached its peak. Therefore, Wang Haixin believes that nitrogen oxide phosphor technology will mature in the next 5-6 years. To upgrade to the current level of YAG, first to break through the monopoly of YAG phosphor patents.
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