Patent ID: 8482737
Filing Date: 2013-07-09
Classification: G01B,G01J,G02B

Abstract:
1. A variable spectroscopic element characterized in that the variable spectroscopic element comprises a pair of optical substrates which are arranged opposite at a distance from each other, first, second, third, and fourth capacitive sensors each of which includes a pair of electrodes placed on the surfaces of the pair of the optical substrates opposite to each other respectively and each of which detects a distance between the surfaces of the pair of the optical substrates opposite to each other at the each placed position, and first, second, third, and fourth actuators which move at least one of the pair of the optical substrates relative to the other optical substrate to change a distance between the surfaces of the pair of the optical substrates opposite to each other, the first and third capacitive sensors are placed at positions at which the first and third capacitive sensors are symmetrical with respect to a line connecting the centers of mass of the surfaces of the pair of the optical substrates opposite to each other, respectively, the second and fourth capacitive sensors are placed at positions at which the second and fourth capacitive sensors are symmetrical with respect to the line connecting the centers of mass of the surfaces of the pair of the optical substrates opposite to each other, respectively, the first, second, third, and 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, second, third, and fourth capacitive sensors respectively, respectively, and the variable spectroscopic element comprises a control unit, the control unit calculating 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, second, third, and fourth capacitive sensors, the control unit calculating with signals from the first and third capacitive sensors a first angle that is made between the surface of the optical substrate perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates and the surface of the moved optical substrate opposite to the surface of the optical substrate perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates, the control unit calculating with signals from the second and fourth capacitive sensors a second angle that is made between the surface of the optical substrate perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates and the surface of the moved optical substrate opposite to the surface of the optical substrate perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates, the control unit driving the first and third actuators on the basis of the distance between the centers of mass and the first angle, and the control unit driving the second and fourth actuators on the basis of the distance between the centers of mass and the second angle.