Overview of Lighting-Class LED Development Status and Manufacturers

With the improvement of LED efficiency and technological progress, LED applications have gradually expanded from backlight and indicator light applications to lighting applications. However, in order to solve the problem of light and heat, each LED manufacturer has its own solutions from chips to packaging and even lamps, with a wide variety of product specifications. Therefore, LEDinside has compiled the current development status of lighting-grade LEDs and the main products of each manufacturer for readers.

Discussion on lighting-grade LED specifications

Lighting-class LEDs can be discussed and classified from many aspects. From the chip side, they can be classified by current into low power (High Brightness LED, 20~150mA), high power (High Power LED, <150mA), AC LED and other types. From the packaging structure, they can be mainly divided into single chip package with a single chip on a single package, or multi-chip package with multiple chips on a single package. Different packaging structures and chips have their own suitable lighting fixture markets.

Figure-1 Lighting-class LED chips and packaging specifications

LED lamps suitable for various specifications of LED

At present, the light sources used in LED lamps of the bulb type are mostly single-crystal or multi-crystal packaged high-power LEDs, AC LEDs, etc. High-power LEDs of single-crystal package are commonly used in lighting products with concentrated light sources and strong directionality, such as MR16 and LED projection lamps. LED bulbs that replace energy-saving bulbs above 10W use multiple packaged high-power LEDs as light sources. AC LEDs are limited by the technical bottleneck of AC LED chips, and most of them are LED bulbs that replace incandescent lamps below 10W. As for light bar type lighting fixtures, most manufacturers currently use low-power multi-crystal packaging, and some manufacturers use high-power multi-crystal packaging.

Figure-2 LED lamps suitable for various specifications of LEDs

As for the cost comparison between LED light sources and traditional light sources, the current LED $/Lm (Lumen per dollar) is around USD 0.01~0.02. As LED prices fell sharply last year, the price difference compared to traditional energy-saving bulbs has narrowed from 5~10 times last year to 2~4 times, which is one of the reasons why LED lighting has gradually heated up since this year.

However, since the traditional lighting market is very mature, the brightness and price of traditional lighting do not change in the same proportion, but LED is different. Since LED is a semiconductor component, the price and brightness will increase in the same proportion. Considering the price, the penetration rate of LED bulbs below 10W is still the highest. As for LED light strips, since the price difference of the product is more than 20 times that of traditional light tubes, it is currently only available for commercial spaces or government bidding.

Figure-3 Comparison of $/Lm between LED and fluorescent lamp

CREE is an integrated supplier from upstream chips to packaging. The Xlamp series launched in recent years has been well received in lighting-level LEDs, and is very competitive in terms of luminous efficiency and lifespan. The main reason is that the chip material uses silicon carbide substrates to replace sapphire substrates. The thermal conductivity of silicon carbide substrates is almost 10 times that of sapphire substrates (Silicone Carbide has 10 times Vertical thermal characteristics than Saphire), and it is both thermally and electrically conductive and can directly conduct heat vertically. In addition, there are unique patented technologies in the formulation and coating of phosphors. At this stage, CREE is already able to meet the Energy Star specifications that will be announced by the United States in 2009, and has also passed most of the LM 79 and LM 80 tests. Therefore, for lighting products that want to be shipped to the United States in the future, CREE's LEDs will have considerable advantages.

Currently, the High Power Xlamp series includes XR-E (7090 package), XR-C, XP-E (3535 package), XP-C, and MC-E (7090 4-crystal package). The difference between XP and XR is the size of the package. The size of XP is reduced by nearly 80%, which can effectively reduce the material cost and achieve the same luminous efficiency as the XR series, but the maximum recommended operating current is reduced from 1Amp of the XR series to 700mA. The luminous efficiency of XP-E can reach up to 114Lm/W (cool white)MIN, and has been shipped in large quantities. MC-E uses 4 high-power multi-crystal packages, and the overall luminous flux can reach up to 430Lm@350mA, and the recommended maximum operating current is 700mA.

OSRAM, a lighting giant, is responsible for the LED field through its subsidiary OSRAM Opto Semiconductors. OSRAM Opto Semiconductors has the integration capability from chip to package and has a number of patented white light technologies. On the chip side, high-brightness LEDs are developed using ThinGaN technology. First, a metal film is formed on the InGaN layer, and then the sapphire is peeled off. In this way, the metal film will produce a mapping effect and obtain more light extraction.

As for the high-power product line, the specifications are divided into Golden DRAGON (1W), Platinum DRAGON (3W), and Diamond DRAGON (5W) according to the power. All of them are single high-power LEDs packaged in PLCC. Taking the current main products of the Golden DRAGON series, LUW W5AM and LCW W5AM, as examples, the luminous flux can reach 112-130 lm and 71-82 lm, and the luminous efficiency is 100 lm/W and 64 lm/W respectively.

Nichia's main products are low-power multi-crystalline packaged LEDs, which are made by connecting multiple low-power LED chips in parallel on a PLCC package. Since each single small chip is allocated a very small current, it can achieve high light efficiency and does not require much heat dissipation. In terms of product strategy, Nichia will also launch high-power LED products this year after cooperating with Lumonus.

The 083 specification launched by Nichia last year is also the preferred specification of many LED lighting manufacturers. Taking the current mainstream 083B as an example, when driven at 300mA and 3.3V, the luminous efficiency can reach 100Lm/W.

Toyoda Gosei (TG), a Japanese company with a high market share in the 3C backlight field, will also launch a 3W high-power LED product this year. It adopts a single-chip package and uses Flip chip technology to invert the high-power LED on the ceramic substrate, and increases the number of refractions through the reflective layer at the bottom. Since there is no need for a lead frame, there is no problem of lead frame shielding, which helps to improve the luminous efficiency. The luminous efficiency can reach 80Lm/W, and the product size is only 3.5*3.5mm. This product is made of inorganic materials and has the advantages of high reliability and long life. It is currently in the sample delivery stage and is expected to be mass-produced in the middle of this year.

Edison Optoelectronics is a well-known high-power LED packaging manufacturer in Taiwan. High-power LED components are mainly packaged in the form of Lead frame, and smaller COB package components were launched in the second half of 2008. The LED specifications that can be supplied range from 1W to 100W.

Take Ediexeon ARC as an example. It uses Taiwan chips and lead frame single crystal packaging, and provides 1W/3W specifications. At 350mA, the luminous efficiency can reach 100Lm/W. The actual light decay is about 3% after 3000 hours. It is mainly used in indoor and commercial space lighting fixtures.

Another series, Edistar, uses high-power polycrystalline packaging on a ceramic substrate. The specifications are 50W/100W, the luminous flux can reach 4000/7000Lm, and the luminous efficiency can reach 70Lm/W. Since it can be directly applied to street lamps, it has a high degree of customer inquiries. However, since the heat dissipation problem of high-power polycrystalline packaging is not easy to handle, it will affect the light efficiency and life. Therefore, customers who want to use lamps must have considerable heat dissipation ability before considering purchasing this specification.

Chi Han Optoelectronics Co., Ltd. was founded in 2004. It applied for a patent in the United States through its parent company LUSTROUS. Chi Han manufactures and sells the products under the LUSTROUS brand.

Chi Han's General Manager Liu Jiaqi particularly emphasized the company's own high-power COB packaging patent. Since COB packaging on the market is almost all parallel structure, only Chi Han has the ability to make vertical structure. Its high-power LED components are COB packaged on silicon wafers, and white light is mixed through nitride two-color phosphors, and an optical treatment is added after packaging.

The main product specifications range from 5W to 10W, and 15W products will be developed in the future. The current new products are mainly in the following three specifications: Diamond/Diamond Pro series have a luminous efficiency of 70-80Lm/W and a CRI of about 75%. The Crystal series has a color rendering index of up to 92%, which is suitable for department stores and display cabinets. The company's high-power LED components have a lifespan of about 15,000 hours.

Xinqiang Optoelectronics, which used to focus more on the field of LED street lights, has gradually changed its product strategy. Since 2008, it has mainly promoted its light source engine and developed a variety of indoor or commercial lighting fixtures. Chairman Chen Zhenxian of Xinqiang Optoelectronics emphasized that the company has many patents such as chips, packaging, and heat dissipation. Therefore, Xinqiang's LED components are designed by itself from the chip end and outsourced. The subsequent packaging and heat dissipation engine are integrated into one line, making it one of the few high-power LED suppliers in Taiwan that can integrate chips into packaging.

NeoPac Emitter, the latest product of Xinqiang, is a high-power multi-crystalline packaged LED component. The luminous flux of a 30W LED can be maintained at 1,500Lm, and the size is only 14.1x14.1mm. Although the luminous efficiency is only 50Lm/W, the junction temperature can be controlled at 60°C with its own heat dissipation module, thereby ensuring the durability of the LED light source and maintaining its light characteristics. Chairman Chen Zhenxian emphasized that the current measured light decay data has reached 21,000 hours, and it is estimated that the product life can reach more than 60,000 hours at room temperature of 25°C. This year, the 70Lm/W NeoPac Emitter specification will also be launched.