Laser diode switching system

Abstract

An improved technique for a laser rangefinder includes a pulsed laser sending out a repetition of light pulses and the received signal (light pulse and noise components combined) being analyzed by continuous averaging of successive received signal discrete time sequences, each sequence beginning with the onset of transmitted laser light. Also, a circuit generates high potentials for the laser diode driving circuitry that simultaneously drives the laser diode, having at least one of several beneficial characteristics: It is conveniently synchronous with the light pulse send/receive process to reduce the effects of noise on the receive section. It is energy efficient in converting low battery potentials to higher voltages. Finally, it utilizes a minimized number of components, leading to high product economy.

1 . A laser diode system comprising: 
 a switching transistor, configured to be driven by a continuous pulse wave signal of substantially constant duty, to selectively render conductive and non-conductive the switching transistor;    an inductor coupled to store energy provided from the switching transistor while the switching transistor is conductive;    a capacitor coupled to the inductor to receive and store charge when the switching transistor is non-conductive; and    a laser diode coupled to the inductor and through which, when the switching transistor is conductive, the capacitor discharges.    
   
   
       2 . The system of  claim 1 , further comprising: 
 a first resistor through which charge is provided from the capacitor, along with the laser diode, to maintain a reverse voltage across the laser diode lower than a damage threshold of the laser diode.    
   
   
       3 . The system of  claim 1 , further comprising: 
 a second resistor coupled in parallel with the laser diode.    
   
   
       4 - 10 . (canceled)  
   
   
       11 . The system of  claim 1 , wherein the capacitor is coupled to the inductor via the laser diode.  
   
   
       12 . The system of  claim 1 , wherein the laser diode is coupled between the inductor and the switching transistor.  
   
   
       13 . The system of  claim 1 , wherein the laser diode is coupled in parallel to the switching transistor.  
   
   
       14 . The system of  claim 1 , wherein the inductance of the inductor is such that a resonant frequency of the inductor with the capacitance has a half period equal to a non-conductive period of the switching transistor as determined by the continuous pulse wave signal.  
   
   
       15 . The system of  claim 14 , wherein a half width of a light pulse emitted from the laser diode is in the range of about 9 to 12 nsec.