The industry at the seminar on "current situation and the task of white LED"

[Nikkei BP news]

Figure 1: "white LED 2005" seminar site Figure 2: Nichia Long Bang hand using semiconductor laser white light emitting part of white light emitting diode (LED) light emitting efficiency is improved rapidly, the rapid increase in brightness. "When can the white LED exceed the fluorescent lamp to get the luminous efficiency above 100lm/W? What are the issues that need to be addressed in the field of lighting equipment, vehicle equipment and LCD panels?" These problems aroused strong interest of the participants. In June 24, 2005, sponsored by the "Nikkei Electronics" magazine's "white LED 2005 - to achieve high power to the lighting and the vehicle in the field of universal technology seminar, Japan domestic LED manufacturers on the development trend of high power white LED in Japan's domestic lighting equipment manufacturers with lighting equipment for white LED application project delivered a speech (Fig. 1). In the technical release, some predicted that more than 100lm/W luminous efficiency as early as 2008, while others introduced the characteristics of high-power white LED is currently being developed. In addition, there are a lot of speech citing "electrical characteristics of white LED exist serious instability" and "if there is no non white LED can not use equipment, it is hard to popularize trend" explosive issues.

"Comparable to the luminous efficiency of fluorescent lamps" may have to wait until 2008

In a speech delivered by the LED manufacturers, 100lm/W luminous efficiency on the realization of time, CITIZEN made the most challenging forecast. In the speech, the company introduced shortly before the release of the luminous efficiency (70lm/W) and flux (each package 245lm) are electrical characteristics and circuit structure of the world's highest white LED, and the luminous efficiency of the development blueprint also discloses. Allegedly, the input power of 1W class LED will reach 110lm/W in early 2008. It is said that we have found the technical problems and solutions to improve the luminous efficiency to 90lm/W. 70lm/W white LED is the use of 24 square 0.3mm blue LED chip, and then with a high heat dissipation package to achieve.

TOYOTA synthetic open development blueprint, said the 100lm/W luminous efficiency in the end of 2008 to achieve the beginning of the year to early 2009. The company believes that while improving luminous efficiency, but also need to expand the scope of white LED light-emitting color. To this end, the need for new research on fluorescent materials, and claimed that the company is currently developing the "BOS (barium aluminum garnet)" type of fluorescent material is very suitable for later white LED. Compared with the YAG fluorescent material of ordinary white LED, BOS fluorescent material and LED chip with the light color in the range of CIE more than 2 times in the chromaticity diagram. Even with the blue LED chip or near ultraviolet LED chip can effectively stimulate the luminescence of BOS fluorescent material. Although the YAG phosphor can be effectively excited by blue light, it can hardly be excited by near ultraviolet light.

Brightness has reached the standard, the subject is how to improve the instability of electrical characteristics

Nichia talked about the realization of the 100lm/W luminous efficiency of white LED development blueprint, also talked about how to white LED as a light source to the popularity of lighting equipment. White LED in order to widely spread to the field of lighting equipment, there are two major issues. One is how to improve the performance as a lighting device, two is the location of lighting equipment. For the first issue, the current development direction of the company is: in order to improve the luminous efficiency, the interface design of LED chip and the bottom convex sapphire GaN compound semiconductor, in order to improve the light emitting efficiency of LED chip. In addition, not only to improve the luminous efficiency of the LED chip itself to improve, but also must consider the configuration of LED, and how to improve the efficiency of LED power supply and other issues, as a light source system development. Therefore, it is necessary to cooperate with equipment manufacturers and other related fields.

As for the positioning of the lighting equipment, the company said: even if the white LED can become a source of lighting equipment, fluorescent lamps and incandescent lamps and other traditional light will not disappear. In the future, it may be possible to make full use of LED with small, high degree of freedom of the configuration of the lighting equipment." (Nichia second business plan of the Department of business planning minister Ohguro Hiroki agent), and stressed the need for co-operation with LED industry and lighting industry.

On the white LED lighting market positioning and future topics, Matsushita Electric lighting manufacturers from the position of the speech delivered a speech. This paper introduces the present situation of white LED lighting with the flashlight and the self made small mirror with white LED. However, white LED is currently used only for part of the lighting field. In addition, also talked about the success and failure of the case of commodity development and other insider, the atmosphere has been very active.

As a future issue, Matsushita mentioned the following points: one is to further improve the optical power of the white LED two is to improve the color temperature and the forward voltage (VF) characteristics of the instability, three is to reduce the unit cost of flux. In terms of improving optical power, the company released each package luminous flux of 250lm white LED module, for example, said that basically has reached the expected standard. However, in terms of the characteristics of the instability, the company said, fluorescent lamps and incandescent lamp does not exist the problem of instability. Therefore, the characteristics of LED is unstable - LED industry in this knowledge in the lighting industry simply does not work. at present