| 摘要 |
In one embodiment, sub-micron size granules (34) of TiO 2, ZrO 2, or other white colored non-phosphor inert granules are mixed with a silicone encapsulant (32) and applied over an LED (10). In one experiment, the granules increased the light output of a GaN LED more than 5% when the inert material was between about 2.5-5% by weight of the encapsulant. Generally, a percentage of the inert material greater than 5% begins to reduce the light output. If the LED has a yellowish YAG phosphor coating, the white granules in the encapsulant make the LED appear whiter when the LED is in an off state, which is a more pleasing color when the LED is used as a white light flash (42) in small cameras (40). The addition of the granules also reduces the variation of color temperature over the view angle and position over the LED, which is important for a camera flash and projection applications. |
