Microelectromechanical modulation device and microelectromechanical modulation device array, and image forming apparatus

1. A microelectromechanical modulation device comprising:

a movable portion, which is supported to be elastically and bi-directionally displaced and which has a modulation function; and

a plurality of driving sources operative to apply a first physical action force and a second physical action force to said movable portion,

wherein when said movable portion is displacement-driven in a first direction, the second physical action force is applied to said movable portion in a second direction different from the first direction by said drive sources to suppress oscillation of said movable portion while said movable portion is transited in the first direction, and

wherein the first physical action force and the second physical action force are applied to the movable portion simultaneously.

2. The microelectromechanical modulation device according to claim 1 , wherein

the first physical action force is applied to said movable portion by said drive sources in the first direction while said movable portion is transited in the second direction after said movable portion is displacement-driven in the first direction.

3. The microelectromechanical modulation device according to claim 1 , wherein

the first physical action force and the second physical action force are exerted to a plurality of points of action of said movable portion.

4. The microelectromechanical modulation device according to claim 1 ,

wherein when said movable portion reaches a final position of displacement in a specific direction, a speed of said movable portion is substantially 0.

5. The microelectromechanical modulation device according to claim 1 ,

wherein the first physical action force and the second physical action force, which are exerted by said drive sources and which displaces said movable portion in the first direction and the second direction, are electrostatic force.

6. The microelectromechanical modulation device according to claim 1 , wherein

each of the first physical action forces and the second physical action force is applied so that a magnitude of the first physical action force and the second physical action force varies with time according to a pulse wave form whose ordinates represent magnitudes and whose abscissa represent time.

7. The microelectromechanical modulation device according to claim 6 ,

wherein wherein the first physical action force and the second physical action force are generated so that magnitudes of the first physical action forces and the second physical action force vary with time according to a plurality of pulse waveforms.

8. The microelectromechanical modulation device according to claim 1 ,

wherein a plurality of physical action forces can be set corresponding to each of directions of transition of said movable portion.

9. The microelectromechanical modulation device according to claim 1 ,

wherein when said movable portion reaches a final position of displacement in a specific direction, said movable portion touches a stopping member and is stopped.

10. A microelectromechanical modulation device array comprising said microelectromechanical modulation devices according to claim 1 , which are one-dimensionally or two-dimensionally arranged.

11. The microelectromechanical modulation device array according to claim 10 ,

wherein each of said microelectromechanical modulation devices has a driving circuit including a memory circuit; and

at least one of a plurality of electrodes is provided on said movable portion and at least two fixed portions facing said movable portion is a signal electrode, to which an device displacement signal outputted from said driving circuit is inputted, and another of said plurality of electrodes is a common electrode.

12. The microelectromechanical modulation device array according to claim 10 , wherein the modulation device further comprising:

a control portion adapted to modulation-drive each of said movable portions.

13. An image forming apparatus comprising:

a light source;

the microelectromechanical modulation device array according to claim 10 ;

an illuminating optical system adapted to irradiate light, which is outputted from said light source, onto said microelectromechanical modulation device array; and

a projection optical system adapted to project light, which is outputted from said microelectromechanical modulation device array, onto an image forming surface.