Variable spectrum element

摘要

A variable spectrum element includes: first and third sensors which 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 which 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 which are placed on lines running from the center of mass of the surface of each of the pair of the optical substrates opposite to each other to the centers of the first to fourth sensors respectively, respectively.

主权项

1. A variable spectrum element comprising
a pair of optical substrates arranged opposite at a distance from each other, first, second, third, and fourth capacitive sensors each including a pair of electrodes that are placed on surfaces of the pair of the optical substrates opposite to each other respectively and each detecting a distance between the surfaces of the pair of the optical substrates opposite to each other at each placed position, and first, second, third, and fourth actuators relatively moving 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 being placed at positions at which the first and third capacitive sensors are symmetrical with respect to a line connecting centers of mass of the surfaces of the pair of the optical substrates opposite to each other, respectively, the second and fourth capacitive sensors being 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 being placed on lines running from the center of mass of the surface of each 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 spectrum element comprising 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 a first angle that is made between a surface perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates and the surface of the relatively moved optical substrate of the surfaces of the pair of the optical substrates opposite to each other, with signals from the first and third capacitive sensors, the control unit calculating a second angle that is made between the surface perpendicular to the line connecting the centers of mass of the surfaces of the pair of the optical substrates and the surface of the relatively moved optical substrate of the surfaces of the pair of the optical substrates opposite to each other, with signals from the second and fourth capacitive sensors, the control unit calculating a difference between a distance between the surfaces of the pair of the optical substrates opposite to each other at a position of the first actuator placed on the pair of the optical substrates and a distance between the surfaces of the pair of the optical substrates opposite to each other at a position of the second actuator placed on the pair of the optical substrate, with signals from the first and second capacitive sensors, the control unit actuating the first and third actuators on the basis of the distance between the centers of mass of the surfaces of the optical substrates, the first angle, and the difference between the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the first actuator and the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the second actuator, the control unit actuating the second and fourth actuators on the basis of the distance between the centers of mass of the surfaces of the optical substrates, the second angle, and the difference between the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the first actuator and the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the second actuator, and the control unit repeating the process which ranges from the calculation of a distance between the centers of mass of the surfaces of the optical substrates to the actuations of the second and fourth actuators until the difference between the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the first actuator and the distance between the surfaces of the pair of the optical substrates opposite to each other at the placed position of the second actuator becomes approximately equal to zero.