1. Field of Invention
The invention relates to a cooling device and, in particular, to an air flow channel.
2. Description of the Prior Art
FIG. 1 shows the cooling method for a conventional projector lamp. Normally, a blower 800 directly blows cooling air into the lamp reflector 700, taking away heat generated by the projector lamp 500. The cooling places of the projector lamp 500 are mainly the high-temperature points above and below the filament 510, the soldering point 520, and the end points 530. Each high-temperature point has to be controlled within a certain temperature range. Aside from the projector lamp 500, the lamp reflector 700 has to be cooled below a predetermined temperature in order to prevent the lamp reflector from breaking. Using the conventional cooling method on the projector lamp 500, the cooling air has a directly impact on the projector lamp 500 instead of cooling each of the high-temperature points according to the required temperature ranges. Moreover, the cooling air first flows by the end point 530, the soldering point 520, and the filament 510 and absorbs their heat before reaching the bottom of the lamp reflector 700. However, these high-temperature points have temperatures higher than the bottom of the lamp reflector 700. The cooling air after absorbing heat from them is very difficult to further cool down the bottom of the lamp reflector 700. If one solves the problem by increasing the fan speed, the temperatures are those high-temperature points will be lowered too much out of the required ranges. This method of first cooling down the high-temperature points with higher temperatures before cooling down the lamp reflector has the drawback that when the temperature of the lamp reflector becomes too high, adjusting the fan speed to lower the temperature of the lamp reflector will render the temperature of the filament out of the specific range. This makes the temperature control very difficult.
As described, the prior art results in non-uniform cooling on different parts of the projector lamp 500 and the lamp reflector 700 or cannot cool the system in such a way that the projector lamp 500 and the lamp reflector 700 fall right within the desired temperature ranges. These effects will affect the performance and lifetime of the projector lamp and the lamp reflector. Thus, it is desirable to provide a better cooling system.