High-brightness white LED technology and market analysis

Dalian Hanguang Industrial Park Han Qi Dr. Liu Li, School of Materials, Shanghai University
Summary
As brightness increases and prices decrease, white LEDs have an increasing market potential in general lighting. The use of white LEDs in the general lighting industry will have a positive impact on national or regional energy strategies and environmental strategies.

White LEDs are small in size, can be packaged in a flat package, or used in multiple or multiple combinations depending on the environment or condition, and have low heat generation, long luminescence life (more than 50,000 hours), are not easily broken, and are extremely shock-resistant and Impact resistance, can be used in harsh conditions and other characteristics. White LEDs have high luminous efficiency, energy saving, no heat radiation, no heavy metals such as mercury, no pollution, and waste disposal problems. They are regarded as the "green lighting source" of tomorrow, and in the near future, It replaces the current mainstream incandescent bulbs and firefly (day) lights for the lighting market. The development of white LED lighting industry will affect the energy strategy and environmental protection strategy of a country and region. Therefore, various countries have carried out support for the LED semiconductor lighting industry as a major national development. China's Taiwan region has also invested heavily in research and development. . International companies such as GE, Siemens, Philips, Siemens, and Hewlett-Packard have been actively involved in the research and development of white LEDs.

The market for white LEDs is the most promising market for lighting sources with strong market potential in the LED industry. According to estimates by Frost & Sullivan, the global lighting source market is steadily climbing at an average rate of 5% per year. Among them, white LEDs are more accessible to the incandescent bulbs and fluorescent lamps market. These two products are the most popular for residential lighting. The light source, the market potential of white LEDs in the future can be said to be quite huge.

First, white light LED lighting principle

The way of white LED illumination can be divided into two types, single crystal type and polycrystalline type, mainly according to the number of LED light emitting diodes used.

The first type is a single crystal type, that is, a single-color LED light-emitting diode plus a corresponding phosphor, just like the fluorescent light, the LED light-emitting diode is used to excite the phosphor to emit light. Two methods are usually used, one is that the blue LED light emitting diode excites the yellow phosphor to generate white light, and the other is that the ultraviolet light LED excites the RGB three-wavelength fluorescent powder to generate white light. Many manufacturers are mainly engaged in the research of white LEDs. They usually start with R&D and mass production of blue LEDs. After the technology of blue LEDs, they will start to develop white LEDs. However, the most commonly used blue LEDs stimulate yellow phosphors to produce white light, but The luminous efficiency of using blue LEDs to emit white light is still insufficient. Many manufacturers have begun to develop toward ultraviolet LEDs by using ultraviolet LEDs and RGB three-wavelength phosphors to achieve white light effects. Blu-ray is much better. The method of ultraviolet LED plus RGB three-wavelength phosphor powder is the key technology in the high-efficiency phosphor synthesis method, which is a technique for how to effectively attach the phosphor to the crystal grains.

The other is a polymorph type, that is, using two or more complementary two-color LED light-emitting diodes or mixing three primary color LED light-emitting diodes to form white light. The use of a polycrystalline type to generate white light, because different color LED light-emitting diodes have different driving voltages, light-emitting outputs, temperature characteristics, and lifetimes, so white light is produced in a manner using polycrystalline LED light-emitting diodes. The way in which LEDs produce white light is complicated, and because of the large number of LED light-emitting diodes, the cost of polycrystalline LEDs is also high; if a single crystal type is used, only a single-color LED light-emitting diode element can be used, and The design on the drive circuit will be easier. Therefore, many manufacturers now use single crystal LEDs as the development direction of white LEDs.

2. Market Overview:

LED technology has developed rapidly in recent years, brightness has been continuously improved, and prices have been continuously reduced. In addition to the original LED market, in the general lighting, the market is also expanding, and the brightness and price are gradually approaching the traditional source. Due to the turmoil in the world's oil-producing regions, the global energy shortage has once again become the focus of attention. The development of the LED industry will have a huge impact on energy and environmental policies in a region. The United States, Japan, Europe, and South Korea have all established state-level R&D organizations to accelerate technology development and mass production.

At this stage, there is still a long way to go before the actual entry into the white LED lighting era. Due to the luminous efficiency and cost of white LEDs, the luminous efficiency of white LEDs can reach 100lm/W in 2010 and 200lm/W in 2020. If the process of white LEDs speeds up, it will be a commercial product that will gradually appear in 2005, and it will be used in large quantities after 2010.

In the lighting market, according to Frost & Sullivan's estimates, the global market for incandescent bulbs and fluorescent lamps in 2000 was about $4.3 billion, with an annual growth rate of about 5%, which is about 2.5 times the size of the global visible LED market in 2000. Therefore, the development of the lighting market is quite large. Reed Electronics Research's global white LEDs are expected to grow to a market size of US$118 million in 2000, and will maintain a growth rate of around 40% in the next three years, reaching a market size of US$270 million in 2003. In the future, the cost of white LEDs will be further reduced. In addition to the existing mobile phone backlights and small-size LCD backlights, if the general lighting market starts, the white LED market will have greater market potential. White LEDs are estimated from 2004. At the beginning, the market energy will be gradually released, and the demand will gradually increase.

At this stage, the application of white LEDs, in terms of lighting, is mainly used for reading lamps, decorative lights, etc. in the car, and about 95% of the rest are for small-size LCD backlights.

1. The white LED market is the largest market for screen backlights for color mobile phones.
Although white LEDs have a service life of up to 100,000 hours, they must be operated in a low-current environment. Currently, the product is mainly used for small-sized backlights. For each application market, color screen phones need to be equipped with white LEDs. Backlight, and color screen mobile phones will become the development trend of the mobile phone market in the next few years. According to the industry's market forecast for color screen mobile phones, the proportion of color mobile phones in 2004 is about 40%, and in 2005 it is estimated to reach 55% to 60%. The demand for color screen mobile phones is about 450 million a year and the backlight for the screen needs 2 - 4 white LEDs to estimate. The screen backlight for color mobile phones needs about 500-100 million a year. In addition, since white LEDs have begun to adopt In the mobile phone with a digital camera flash, this year's mobile phone with a digital camera is about 15%, next year is expected to increase to 20%, such as the flash requires about 3-4 estimates, the annual demand is about 400 million. Secondly, in terms of backlights for PDAs and digital cameras, according to the estimated value of the Taiwan Industrial Technology Research Institute, the PDAs shipped about 25 million units in 2003, each using about 6-8 white LEDs. Estimated that it will cost about 50 million; if it is digital camera, the global digital camera shipments in 2003 will be about 30 million units, with an estimated 4-6 pieces per unit, and the demand will be about 200 million units. In view of this, the demand for white LEDs will still be dominated by the color screen mobile phone backlight market.

2. White LED is currently based on small-size LCD backlights.
Cold cathode fluorescent lamps (CCFLs) have the advantages of brighter brightness and higher luminous efficiency than other backlight technologies. However, in terms of small-sized LCDs, the size of backlights is relatively strict, but cold-cathode fluorescent lamps with small diameters are manufactured. The technical difficulty is high, and the cost is not much advantage. Therefore, the cold cathode fluorescent lamp is mostly used in displays of more than 4 inches (while the screen size of the general mobile phone is between 1.5 inches and 2.2 inches, the size of the digital camera is also considered due to the thinness and lightness. In addition, in terms of large-size LCD backlights, cold cathode fluorescent lamps at this stage have an absolute advantage in terms of brightness and price required for large sizes, so cold cathode fluorescent lamps are used in large-sized LCD backlights. Therefore, the boundary between white LEDs as LCD backlights and cold cathode fluorescent lamps as LCD backlights is that small-size LCDs use white LEDs, and large and medium-size LCDs (such as LCD screens, LCD TVs) use cold cathode fluorescent lamps. For example, when the brightness of the white LED is increased and the cost is further improved, in the case of a large-sized LCD, the white LED will be replaced with a cold cathode fluorescent lamp as a backlight. As a result, considering the market potential of large-size LCDs in PCs and TVs, the demand for white LEDs as large-size LCD backlights is quite alarming.

3. The biggest market for white LEDs is the general lighting market.
The industry's most optimistic about the white LED market is the general lighting market. At this stage, the luminous efficiency of white LEDs has reached 30lm/W (the average incandescent bulb luminous efficiency is 15lm/W), but if white LEDs really occupy the general lighting market. In a certain market, there is an opportunity to increase the efficiency of white LED illumination to 60-100 lm/W. From the perspective of luminous efficiency, once the white LED exceeds 60 lm/W (equivalent to 20W fluorescent lamp), it can be popularized in the lighting market. If the efficiency can be increased to 80 lm/W, it will be popularized in various household lamps. However, white LEDs really need to occupy the general lighting market. In addition to the great improvement in luminous efficiency and power, cost is also a very important factor. In terms of luminous efficiency and cost ratio, the cost of white LEDs in 2001 was about US$1/lm. In 2002, it fell to 0.1 US dollars / lm, if the cost can be reduced to 0.01 US dollars / lm, because white LED is a green energy source, it is expected that there will be a market that can completely replace the existing general lighting.

Third, the problem of patents related to white LED
At present, the world's leading manufacturers of high-brightness white LEDs: Nichia, Orsam, Matsushita, Lumileds, Toyota Gosei, Stanley, Toshiba, Citizen, these manufacturers have more patents in LED materials and processes, and generally do not use patent licensing to release technology. In terms of market competitiveness and positioning, Nichia, Toyota Gosei, and Cree are leading the way in high-end technologies such as Blu-ray and white light, while European and American manufacturers Lumileds and Osram are the most complete in vertical integration, because LEDs have special and general lighting, LED The development of various applications such as display screens and mobile phone backlights, so the market development trend, sales channels and the layout of upstream and downstream raw materials and key industry chains will be the key to increasing the market share of large international manufacturers in the market.
In addition, white LEDs are involved in patent issues. Nichia successfully mass-produced GaN blue LEDs in November 1993, almost monopolizing the entire Blu-ray market. However, with the improvement of the quality of Toyota Gosei and Cree blue LEDs, Nichia has been threatened. Since 1996, Nichia has risen. A series of patent litigation disputes, because Nichia did not pass the patent authorization release technology, attempted to monopolize the market through patent technology, was attacked by quite a number of companies, and repeatedly failed in many lawsuits. In 2002, it began to cooperate with Osram, Toyota Gosei, Lumileds. Cree reached a settlement and was forced to begin cross-licensing patents with the above companies, and could use the patented technology of both parties to end the six-year lawsuit. Nichia's patent monopoly basically draws a full stop. In October 2002, Osram licensed the white LED manufacturing technology to Rohm. However, in recent years, Nichia has not accused Osram and Rohm of this, and the ice of Nichia's patent monopoly has begun to melt. The lawsuit will take time to conduct an infringement investigation, and a large amount of money will fall into the deep pocket of the lawyer. Due to the surge in demand in the LED market, no company can dominate the market. Because the use of LED lighting affects energy strategy and environmental protection strategy, each country has a certain reservation on the Nichia patent litigation. This affects the results of the Nichia patent litigation to a certain extent.

It is worth noting that the recent Taiwanese manufacturer Yiguang has also obtained the official authorization of Osram white LED. The follow-up of international large-scale manufacturers will be accelerated. In the future, domestic LED manufacturers will continue to obtain, which will help Taiwan manufacturers enter the white LED. market.

In early 2004, Lite-On signed an interactive licensing contract with Osram. Lite-On will be able to produce and sell white LEDs without patent restrictions. The main application markets are backlight modules such as mobile phone panels, mobile phone buttons, digital cameras, projectors, PDAs, and LCD monitors. And car audio panel. Since Lite-On is mutually authorized with Osram, the market expects that the company will pay a patent license fee that is significantly lower than that of Everlight. The mutual authorization of Lite-On and Osram will melt the ice in the use of white LED patents , and also give many LED companies the direction indicated in the use of patents. Perhaps, in the near future, the era of relying on patents to dominate the market will never go. Returned.

LED patent issues have been a major problem plaguing LED manufacturers in Taiwan and China. Japan and the United States have always adopted the method of non-sale of patents. Taiwan’s LED manufacturers have been subject to patent restrictions and legal proceedings by Japanese and American companies. Yiguang and Lite-On have reached patent licenses with European and American companies, and will give Taiwan and China. Continental LED manufacturers provide warnings on LED patent issues.

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