Projection system and control method of driving current therefor

A projection system comprising:

• an illumination module, a filter wheel, a control device, a light valve, and a projection lens,
• wherein the illumination module is configured to provide an illumination beam, and the illumination module comprises a power supply and a light source, wherein
• the power supply provides a driving current, and
• the light source is driven by the driving current and provides the illumination beam,
• wherein the filter wheel is disposed on a transmission path of the illumination beam, configured to receive the illumination beam and provide a plurality of filtered beams, wherein the illumination beam passes through the filter wheel during a first period and a first filtered beam is generated, the illumination beam passes through the filter wheel during a second period and a second filtered beam is generated, and the plurality of filtered beams comprise the first filtered beam and the second filtered beam, and wherein the plurality of filtered beams further comprise an intermediate filtered beam generated from the illumination beam passing through the filter wheel during an intermediate period between the first period and the second period,
• wherein the control device is configured to control the power supply, so that the power supply continuously provides the driving current from the first period, through the intermediate period, to the second period, so as to drive the light source,
• wherein the light valve is disposed on transmission paths of the plurality of filtered beams and configured to convert the plurality of filtered beams into an image beam,
• wherein the projection lens is disposed on a transmission path of the image beam and configured to project the image beam,
• wherein during the first period, the second period, and the intermediate period, the driving current is a first driving current, a second driving current, and an intermediate driving current, respectively;
• and
• wherein an absolute value of a difference between the intermediate driving current and the first driving current is smaller than or equal to one-half of the larger one selected from the intermediate driving current and the first driving current.