Optical pickup and optical storage device

Abstract

An optical pickup for an optical storage device includes a stem, a substrate mounted on the stem, and a laser diode mounted on the substrate. The substrate is integrally formed with an optical signal detector and an error signal detector for focusing error detection and tracking error detection. A cap is mounted on the stem so as to accommodate the substrate and the laser diode. A beam splitter unit including a polarization beam splitter and a beam splitting element is mounted on the cap. A hologram for diffracting a reflected beam toward the error signal detector is interposed between the cap and the beam splitter unit. The substrate is biased at a given potential, and has an insulating film opposed to the stem.

1 - 14 . (canceled)  
   
   
       15 . An optical pickup comprising: 
 a stem;    a substrate mounted on said stem;    a laser diode for outputting a laser beam;    a photodetector provided on said substrate for detecting return light from an object to be irradiated with said laser beam;    a dummy photodetecting region provided on said substrate adjacent to said photodetector;    a dummy electrode formed in said dummy photodetecting region so as to surround said photodetector; and    wiring for connecting said dummy electrode to a ground potential.    
   
   
       16 . An optical pickup according to  claim 15 , wherein: 
 said photodetector comprises a first photodetector for detecting a regenerative signal from said return light, a second photodetector for detecting a servo signal from said laser beam focused on said object, and a third photodetector for monitoring an output from said laser diode; and    said dummy photodetecting region comprises a first dummy photodetecting region provided adjacent to said first photodetector, a second dummy photodetecting region provided adjacent to said second photodetector, and a third dummy photodetecting region provided adjacent to said third photodetector.    
   
   
       17 . An optical pickup according to  claim 16 , wherein said dummy electrode comprises a first dummy electrode formed in said first dummy photodetecting region so as to surround said first photodetector, a second dummy electrode formed in said second dummy photodetecting region so as to surround said second photodetector, and a third dummy electrode formed in said third dummy photodetecting region so as to surround said third photodetector.  
   
   
       18 . An optical pickup according to  claim 15 , further comprising a light shielding member having light absorptivity formed on said substrate so as to cover at least said dummy photodetecting region.  
   
   
       19 . An optical pickup according to  claim 18 , wherein said light shielding member comprises a polyimide film.  
   
   
       20 . An optical storage device capable of at least reading information stored in an optical storage medium, comprising: 
 a base;    a carriage movable along said optical storage medium;    a stem mounted on said base;    a substrate mounted on said stem;    a laser diode for outputting a laser beam;    an objective lens mounted on said carriage for focusing said laser beam from said laser diode onto said optical storage medium;    a photodetector for detecting at least a regenerative signal from return light from said optical storage medium;    a dummy photodetecting region provided on said substrate adjacent to said photodetector;    a dummy electrode formed in said dummy photodetecting region so as to surround said photodetector; and    wiring for connecting said dummy electrode to a ground potential.    
   
   
       21 . An optical storage device according to  claim 20 , wherein: 
 said photodetector comprises a first photodetector for detecting a regenerative signal from said return light, a second photodetector for detecting a servo signal from said laser beam focused on said optical storage medium, and a third photodetector for monitoring an output from said laser diode; and    said dummy photodetecting region comprises a first dummy photodetecting region provided adjacent to said first photodetector, a second dummy photodetecting region provided adjacent to said second photodetector, and a third dummy photodetecting region provided adjacent to said third photodetector.    
   
   
       22 . An optical storage device according to  claim 21 , wherein said dummy electrode comprises a first dummy electrode formed in said first dummy photodetecting region so as to surround said first photodetector, a second dummy electrode formed in said second dummy photodetecting region so as to surround said second photodetector, and a third dummy electrode formed in said third dummy photodetecting region so as to surround said third photodetector.  
   
   
       23 . An optical storage device according to  claim 20 , further comprising a light shielding member having light absorptivity formed on said substrate so as to cover at least said dummy photodetecting region.  
   
   
       24 . An optical storage device according to  claim 23 , wherein said light shielding member comprises a polyimide film.  
   
   
       25 - 28 . (canceled)