| Summary: | 碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 98 === PWM dimming technology driven mainly by tuning the pulse width of the average change in forward current, and thus achieve the purpose of regulating the amount of light output, we can adjust the output stability of the amount of light, it can avoid the main wavelength drift phenomenon is. The resistance and the current control circuit is used to directly control the forward current is designed pulse width modulation of the function is completed by the series an electronic switch, so as long as the adjustment of the optical signal transfer width, we can adjust the forward current pulse, then the amount of light reaching the purpose of adjusting the output. The advantage of this design may with high rapid response, 5 groups respectively LM555 LED light source thread dimming switch mode LED driver architecture.
With 9 pieces LED wavelength chips comprising adjustable light source, adjusted to change the current of LED light mixed light of this ratio, we can assemble any number of sources is multiplied with the color of the spectral distribution function, and therefore a variety of adjustable mixture under different color temperature light effect, color rendering standard for comparison because the reflectivity under color blocks, we can use LED on characteristics of the narrow FWHM(Full Width at Half Maximum) out of CRI are more than 98%.
Since the LED can be used as artificial light source, but with multi-wavelength LED light source device as limited to three kinds of different wavelengths of light changes, light duration, light modulation of the working ratio, frequency or amplitude changes. As the LED’s characteristics, and different LED wavelengths can be formed, the development of artificial multi-wavelength LED light source modulation. Study of multi-wavelength light source may generate a new research field.
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