| 摘要 |
A lighting unit containing an array of LEDs, which are attached to a circuit board. A fan draws air from outside the unit through a filter and directs it onto the back of the board to cool the LEDs. The LEDs are thermally connected to the circuit board by their leads, and both sides of the board may be copper coated to increase thermal conduction. The fan is mounted on resilient means and the unit has a soft start and stop control for the fan to reduce noticeable noise. The fan is started or stoped when the current to the LEDs exceeds or falls bellow a threshold. The array may contain red, green and blue LEDs, each colour being controlled by an external voltage to adjust the output colour. The front section of the unit is sealed around the circuit board to prevent dust accumulating on the LEDs. |
