LED industry in the past in order to profit fully white led 1w beam, once the development of large-size LED chips trying to take this way to achieve the desired goals, but actually exert power white LED continuous beam but will decline more than 1W above, the luminous efficiency is relatively lower 20 30%, in other words, if the brightness of white LED several times larger than the traditional LED, and power consumption characteristics beyond the fluorescent lights, you must first overcome the following four topics: a. inhibition of temperature rise; (b) ensure that the service life; (c) to improve the luminous efficiency; (d) Luminescence Properties of equalization.
Is to reduce the package thermal impedance on temperature rise problems; maintain LED life is to improve the chip shape, a small chip; specific methods to improve the chip architecture, small chip to improve the LED luminous efficiency; As for the light-emitting characteristics of uniform of specific methods is the improvement of the LED package is generally believed that from 2005 to 2006, the white LED is expected to start using the above countermeasures.
Development latitude and longitude to increase power but will cause the package thermal impedance is drastically reduced to below 10K / W, so foreign companies have developed a high temperature white LED attempts to improve the practice, however, the heat than low-power LED High Power LED For more than ten times, and the temperature rise will make the light-emitting efficiency dropped sharply, even if the packaging technology allows high-calorie However, there is the led 10w chip junction temperature may exceed the allowable value, the last industry realize that to solve the cooling problem of the package is the ultimate method.
LED life, for example, to switch to the silica sealing materials and ceramic packaging materials, make the led power 10w service life by 10%, white LED light spectrum contains wavelengths below 450nm short wave length light, traditional epoxy resin sealing material can easily be short-wavelength light damage, the amount of light of high power white LED to accelerate the deterioration of the sealing material, less than one million hours of continuous lighting, according to the test results of the industry, high-power white LED brightness has been reduced by half, simply can not meet the lighting long light source life's basic requirements.
The led power 50w luminous efficiency to improve the chip package structure, can achieve the same level with the low-power white LED, mainly due to the current density increased by more than 2 times, not only is not easily removed from the big chip light, a result, it will cause the luminous efficiency the dilemma of not as good as low-power white LED, improving the electrode structure of the chip, in theory, the light extraction issues can be resolved.
For light-emitting characteristics of uniformity, is generally believed that to improve the uniformity of the white High Power LED 50W phosphor material concentration, and the phosphor production technology should be able to overcome these troubled.