| 主权项 |
1. A slidable light filtering device with two filters, comprising:
a casing having an oblong shape and having a recess therein; a middle section of the recess having a through window; two windings being at two opposite lateral sides of the casing; in installation, the windings winding around the outer sides of the casing; the winding wires of the two windings being wound along identical directions, or opposite directions; a sliding sheet capable of being received into the recess and being movable between the two lateral sides of the casing; each of two lateral sides of the sliding sheet being installed with a first permanent magnet; a middle section of the sliding sheet having two through holes; a first through hole being installed with a first filtering sheet; and a second through hole being installed with a second filtering sheet; an upper cover capable of covering an upper side of the casing so that the sliding sheet being installed in a space between the casing and the cover; a middle section of the cover having a penetrating hole which is positioned to align to the window of the casing so that light passes through the penetrating hole will passes through the through window of the casing; and an electric circuit board being installed in the recess and below the sliding sheet; the electric circuit board having a through hole which is positioned with respective to that of the through window of the casing so that in installing state; the through window is overlapped with the through hole of the electric circuit board; as a result light can pass therethrough; the two windings being electrically connected to the electric circuit board. |
