Optical switch controller and movable body controller

Abstract

In an optical switch controller, in order that residual vibration at movement control of a movable body such as a tilt mirror can be reduced and controlled with high accuracy, a processing unit outputs a driving signal for controlling the angle of the tilt mirror, the driving signal is D/A converted by a D/A converter and then is changed to a high-voltage signal by a high-voltage amplifier to be supplied to the tilt mirror, the electrostatic capacity of the tilt mirror changes corresponding to angle change of the tilt mirror, a mirror-angle detecting unit detects the electrostatic capacity and feeds back it as a correction value to a processing unit, and the processing unit corrects the driving signal using a correction value obtained when the angle of the tilt mirror is actually changed.

1 . An optical switch controller performing angle control of a mirror upon using electrostatic capacity changed corresponding to angular positions, comprising: 
 electrostatic capacity detection means for detecting the electrostatic capacity of said mirror; and    processing means for correcting a driving signal to change the angular position of said mirror at the time of angular position change, on the basis of the electrostatic capacity detected by said electrostatic capacity detection means.    
   
   
       2 . An optical switch controller performing angle control of a mirror upon using electrostatic capacity changed corresponding to angular positions, comprising: 
 a mirror moving at angular position corresponding to one or more values of driving voltages of driving signals based on said driving signals having a plus and a minus driving voltage;    electrostatic capacity detection means for detecting a first electrostatic capacity obtained due to the driving signal of the plus driving voltage and a second electrostatic capacity obtained due to the driving signal of the minus driving voltage, when providing the driving signal of the plus driving voltage and the driving signal of the minus driving voltage for said mirror respectively; and    processing means for correcting the driving signals to change the angular position of said mirror at the time of angular position change, on the basis of said first electrostatic capacity and said second electrostatic capacity detected by said electrostatic capacity detection means.    
   
   
       3 . An optical switch controller performing angle control of a mirror upon using electrostatic capacity changed corresponding to positions, comprising: 
 a mirror moving at angular position corresponding to values of driving voltages of driving signals based on said driving signals having a plus and a minus driving voltage;    electrostatic capacity detection means for detecting a first electrostatic capacity obtained due to the driving signal of the plus driving voltage and a second electrostatic capacity obtained due to the driving signal of the minus driving voltage, when providing the driving signal of the plus driving voltage and the driving signal of the minus driving voltage for said mirror respectively;    electrostatic capacity comparison means for obtaining the difference between the values of said first electrostatic capacity and said second electrostatic capacity detected by said electrostatic capacity detection means; and    processing means for correcting the driving signals to change the angular position of said mirror at the time of angular position change, on the basis of signal of the difference between the values of the electrostatic capacities obtained by said electrostatic capacity comparison means.    
   
   
       4 . An optical switch controller according to  claim 1 , wherein said electrostatic capacity detection means uses an oscillating circuit in which oscillation frequency changes based on variations of said electrostatic capacity.  
   
   
       5 . An optical switch controller according to  claim 4 , wherein the oscillating circuit used as said electrostatic capacity detection means is an LC oscillating circuit whose oscillation frequency changes based on variations of said electrostatic capacity.  
   
   
       6 . An optical switch controller according to  claim 5 , wherein the LC oscillating circuit used as said electrostatic capacity detection means is a Colpitts oscillating circuit whose oscillation frequency changes based on variations of said electrostatic capacity.  
   
   
       7 . An optical switch controller according to  claim 1 , wherein said electrostatic capacity detection means comprises: 
 a resonance circuit whose resonance frequency changes based on variations of said electrostatic capacity; and    a frequency sweeper for sweeping frequencies to provide swept frequency signals for said resonance circuit.    
   
   
       8 . An optical switch controller according to  claim 3 , wherein said electrostatic capacity detection means uses an oscillating circuit for outputting a first oscillation frequency corresponding to said first electrostatic capacity and a second oscillation frequency corresponding to said second electrostatic capacity based on variations in said electrostatic capacity each; and 
 said electrostatic capacity comparison means uses a frequency comparing circuit for obtaining the difference between said first oscillation frequency and said second oscillation frequency which have been output from said electrostatic capacity detection means.    
   
   
       9 . An optical switch controller according to  claim 8 , wherein the frequency comparing circuit used as said electrostatic capacity comparison means outputs signals of different polarities corresponding to respective phase leads and lags of said first oscillation frequency and said second oscillation frequency outputted from said electrostatic capacity detection means; and said processing means corrects said driving signals based on the value of the difference and the signals of polarities outputted from said electrostatic capacity comparison means.  
   
   
       10 . An optical switch controller according to  claim 9 , wherein the frequency comparing circuit used as said electrostatic capacity comparison means is composed of a frequency-voltage conversion means for converting said first oscillation frequency and said second oscillation frequency outputted from said electrostatic capacity detection means into corresponding voltages; in a state where said processing means corrects said driving signals based on the voltage of the value of the difference outputted from said electrostatic capacity comparison means.  
   
   
       11 . An optical switch controller according to  claim 1 , wherein said mirror is supported at the center axis of it and has one end and another end which are able to swing in both directions, and has said first electrostatic capacity between said one end and a first driving electrode facing said one end, and said second electrostatic capacity between said another end and a second driving electrode facing said another end.  
   
   
       12 . A movable body controller performing movement control of a movable body upon using electrostatic capacity changed corresponding to moving positions, comprising: 
 electrostatic capacity detection means for detecting the electrostatic capacity of said movable body; and    processing means for correcting a driving signal to change moving positions of the movable body at the time of moving position change, on the basis of the electrostatic capacity detected by said electrostatic capacity detection means.    
   
   
       13 . An optical switch controller performing angle control of a mirror, comprising: 
 a mirror angle sensor for outputting a periodic signal changing depending on angular positions of said mirror;    a signal period detector for detecting the period of the periodic signal outputted from said mirror angle sensor; and    a controller for controlling the angular position of said mirror on the basis of the period detected by said signal period detector.    
   
   
       14 . An optical switch controller according to  claim 13 , wherein said signal period detector comprises: 
 a multi-value state holding unit for holding a multi-value state by the periodic signal outputted from said mirror angle sensor; and    a state detecting unit for detecting changes in the multi-value state of said multi-value state holding unit by using a system clock faster than said periodic signal.    
   
   
       15 . An optical switch controller according to  claim 13 , wherein said signal period detector and said controller are integrated on the same semiconductor chip.  
   
   
       16 . An optical switch controller according to  claim 13 , wherein said mirror angle sensor is constituted by using an oscillator-type electrostatic capacity sensor which changes said periodic signal depending on variations of the electrostatic capacity caused by changes of the angle position of said mirror.  
   
   
       17 . An optical switch controller according to  claim 13 , wherein said mirror angle sensor is constituted by using an oscillator-type inductance sensor which changes said periodic signal depending on variations of the inductance caused by variations of the angle position of said mirror.