Lens-shifting device

A lens-shifting device for a projector having a lens, the lens-shifting device comprising:

• a base;
• a first axial direction adjusting mechanism, disposed on the base, the first axial direction adjusting mechanism comprising:
• a first fixing rod, fixed on a first side of the base;
• a second fixing rod, fixed on a second side of the base;
• a first sliding plate, slidably mounted on the first fixing rod and the second fixing rod for moving in a first axial direction, wherein a first side of the first sliding plate has a first rack;
• a first gear set, having a first gear and a first worm gear co-axial with the first gear, wherein the first fixing rod passes through the first gear set, such that the first gear and the first worm gear are able to rotate relative to the first fixing rod;
• and
• a second gear set, having a first worm wheel and a second gear co-axial with the first worm wheel and disposed between the first fixing rod and the first rack, wherein the first worm gear is used for driving the first worm wheel and the second gear is used for driving the first rack such that the first sliding plate is able to move relative to the first fixing rod and the second fixing rod along the first axial direction;
• and
• a second axial direction adjusting mechanism, disposed on the first sliding plate, the second axial direction adjusting mechanism comprising:
• a third fixing rod, fixed on a third side of the first sliding plate;
• a fourth fixing rod, fixed on a fourth side of the first sliding plate;
• a second sliding plate, slidably mounted on the third fixing rod and the fourth fixing rod for moving in a second axial direction, wherein the lens is disposed on the second sliding plate and one side of the second sliding plate has a second rack, and the second axial direction is substantially perpendicular to the first axial direction;
• a third gear set having a third gear and a second worm gear co-axial with the third gear, wherein the third fixing rod passes through the third gear such that the third gear and the second worm gear are able to rotate relative to the third fixing rod;
• and
• a fourth gear set, having a second worm wheel and a fourth gear co-axial with the second worm wheel and disposed between the third fixing rod and the second rack, wherein the second worm gear is used for driving the second worm wheel and the fourth gear is used for driving the second rack such that the second sliding plate is able to move relative to the third fixing rod and the fourth fixing rod along the second axial direction.