Controlling scrolls of a screen image

A pointing device comprising:

• a chassis;
• a housing having an opening on its top mounted on the chassis;
• a vertical sensor installed on the chassis below the opening;
• a plurality of horizontal sensors installed on the chassis beside the vertical sensor;
• a control stick vertically installed inside the opening of the housing having a top end and a bottom end wherein the bottom end is in contact with the vertical sensor and the top end protruding from the opening of the housing can be horizontally moved within a predetermined angle with respect to the bottom end of the control stick as its center;
• a plate horizontally installed at the bottom end of the control stick having a bottom side positioned above the horizontal sensors and a vertical sliding channel installed at its middle portion wherein the bottom end of the control stick is slidable and vertically mounted in the vertical sliding channel of the plate, and wherein when the top end of the control stick is horizontally moved, the control stick will move the plate allowing the bottom side of the plate to trigger at least one horizontal sensor, and when the control stick is depressed downward substantially at a vertical angle, the bottom end of the control stick will trigger the vertical sensor and the bottom side of the plate will not trigger the plurality of horizontal sensors;
• and
• a control device electrically connected to the vertical and horizontal sensors for detecting vertical movements of the control stick by using the vertical sensor and generating correspondent vertical signals, and detecting horizontal movements of the control stick by using the horizontal sensors and generating correspondent horizontal signals.