How to Make a White LED

LEDs are an energy-efficient source of light. Since they produce largely monochromatic (single-color) light, however, LEDs aren't particularly adapted for producing white light, which is a mixture of colors. Nevertheless, you can make a white LED using one of two basic approaches: using a phosphor coating or combining several different LEDs of different colors.

Difficulty: Challenging

Instructions

Things You'll Need:

• Blue LED
• Phosphor material
• Clear plastic
• Red LED
• Green LED

1. Decide which approach to take: phosphor coatings or multiple LEDs. If you want to use a phosphor coating, you need just a blue LED. If you want to use just LEDs, you need one each of red, green and blue.

2. Coat the blue LED with a phosphor material. The material should ideally produce a range of light frequencies in the yellow and red regions of the spectrum. This combination of light appears nearly white, although it usually still has some bluish color to it.

3. Encase the LED in plastic to form a lens. The lens helps focus and direct the light.

4. Combine the blue, red and green LEDs into a single package. By tuning these three correctly, you can get white light in the same manner as a pixel on a television set (which is a combination of a red, green and blue element).

5. Use the plastic to encase the LED in a lens.

Tips & Warnings

• Although the use of three different colored LEDs is an appealing alternative to the use of a phosphor coating, it's difficult to get the colors mixed properly. You need to make sure that the light still appears white regardless of the viewing angle, for example.