| 摘要 |
<p>A variable spectroscopic element in which first and third sensors are placed at positions at which the first and third sensors are symmetrical with respect to a line connecting the centers of mass of the surfaces of a pair of optical substrates opposite to each other, respectively, second and fourth sensors are placed at positions at which the second and fourth sensors are symmetrical with respect to the line connecting the centers of mass, respectively, and first to fourth actuators are placed on lines running from the centers of mass of the surfaces of the pair of the optical substrates opposite to each other to the centers of the first to fourth sensors respectively, respectively includes a control unit which calculates a distance between the centers of mass of the surfaces of the pair of the optical substrates opposite to each other with signals from the first to fourth sensors, calculates with signals from the first and third sensors a first angle that is made between the opposite surface of the moved optical substrate and the surface of the optical substrate perpendicular to the line connecting the centers of mass, calculates with signals from the second and fourth sensors a second angle that is made between the surface of the optical substrate perpendicular to the line connecting the centers of mass and the opposite surface of the moved optical substrate, and drives the first to fourth actuators on the basis of the distance between the centers of mass, the first angle, and the second angle.</p> |
