• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.8-15
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• 2004

This paper presents a method of improvement of color mixing in an RGB LED white lamp. The deviation from white light after RGB color mixing results mainly from the difference in the ray direction among LEDs. The authors propose a method using tilted lenses covered over each LED to deflect the overall direction of the ray generated from far-sited LEDs toward the center axis of the lamp. The degree of improvement is evaulated using a color discrimination method based on McAdam ellipse.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.145-147
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• 2003

This paper presents a method of improvement of color mixing in an RGB LED white lamp. The deviation from white light after RGB color mixing results mainly from the difference in the ray direction among LEDs. The authors propose a method using tilted lenses covered over each LED to deflect the overall direction of the ray generated from far-sited LEDs toward the center axis of the lamp. The degree of improvement is evaluated using a color discrimination method based on McAdam ellipse.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.197-199
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• 2002

This paper describes the effects of chip arrangement configurations and the dimension of a reflecting cup upon the light output characteristics of a white lamp composed of RGB LED chips. As a result of simulation, the shorter distance between adjacent chips leads to a relative decrease in the light output efficiency due to inter-chip absorption of quanta, but rather uniform color mixing is expected. Among the factors of designing a reflecting cup it is the tilt angle of the cup wall that plays a determining role upon the variation of the light distribution. The light distribution shows a sudden change of pattern from Lambertian to Batwing at about $35^{\circ}{\sim}40^{\circ}$ of tilt angle in case of a silver-coated wall cup.