Optical pickup device and optical disk drive using the same

Abstract

An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

What is claimed is:  
     
         1 . A light source unit comprising: 
 a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and    a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.    
     
     
         2 . The light source unit according to  claim 1  wherein the light beams output from the plurality of light sources have different wavelengths respectively.  
     
     
         3 . The light source unit according to  claim 1  wherein the changing unit is provided to change the angle of divergence of the light beam in a predetermined plane including an outgoing direction of the light beam having a maximum intensity.  
     
     
         4 . The light source unit according to  claim 1  wherein the changing unit is provided to change respective angles of divergence of two light beams among the light beams output from the plurality of light sources, in two orthogonal planes each including an outgoing direction of one of the two light beams having a maximum intensity.  
     
     
         5 . The light source unit according to  claim 1  wherein the changing unit comprises an optical element.  
     
     
         6 . The light source unit according to  claim 5  wherein said optical element includes a marking for positioning of said optical element with one of the plurality of light sources.  
     
     
         7 . The light source unit according to  claim 5  wherein said optical element includes a marking for positioning of said optical element with said at least one of the plurality of light sources.  
     
     
         8 . The light source unit according to  claim 5  wherein said optical element is provided to change an outgoing direction of the light beam having a maximum intensity in addition to the angle of divergence.  
     
     
         9 . The light source unit according to  claim 5  wherein said optical element is provided such that astigmatism of said optical element is corrected.  
     
     
         10 . The light source unit according to  claim 5  wherein said optical element of the changing unit includes at least one of a positive meniscus lens which reduces the angle of divergence and a negative meniscus lens which enlarges the angle of divergence.  
     
     
         11 . The light source unit according to  claim 5  wherein said optical element is provided to change an angle of divergence of a light beam output from a specific one of the plurality of light sources, and said optical element being arranged at a location where the light beams output from the light sources other than the specific light source are not incident to said optical element.  
     
     
         12 . The light source unit according to  claim 11  wherein said optical element is arranged at the location so that a distance z from a light-emission point of the specific light source to an outgoing plane of said optical element in a Z-axis direction of an XYZ orthogonal coordinate system with an XY plane being the outgoing plane meets requirement conditions: 
         d≦z ≦( x −φ)/{tan(θ1/2)+tan(θ2/2)} 
       where x indicates a distance in an X axis direction between the light-emission point of the specific light source and a light-emission point of an adjacent light source in proximity to the specific light source, θ1 indicates an angle of divergence of a first light beam output in the Z axis direction from the specific light source, θ2 indicates an angle of divergence of a second light beam output in the Z axis direction from the adjacent light source, d indicates a thickness in the Z axis direction of the optical element, and ε indicates a width of a region in the x axis direction, the region being interposed between an optical path of the first light beam and an optical path of the second light beam, and neither the first light beam nor the second light beam passing through the region.  
     
     
         13 . The light source unit according to  claim 1  wherein the changing unit comprises a plurality of optical elements arranged for the plurality of light sources respectively, and each of the plurality of optical elements changing an angle of divergence of a light beam output from a corresponding one of the plurality of light sources, respectively.  
     
     
         14 . The light source unit according to  claim 13  wherein at least two optical elements of the plurality of optical elements are unified.  
     
     
         15 . A light source unit package including a light source unit, a branch optical element reflecting a light beam, incident to the light source unit, in a predetermined direction, and a photodetector receiving the reflected light beam from the branch optical element, wherein the light source unit, the branch optical element and the photodetector are unified, and the light source unit comprising: 
 a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and    a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.    
     
     
         16 . The light source unit package according to  claim 15  wherein the photodetector receives the reflected light beam from the branch optical element without being influenced by the changing unit.  
     
     
         17 . An optical element comprising: 
 a transparent substrate;    a first lens portion provided on the substrate to change an angle of divergence of a first incoming light beam to the optical element; and    a second lens portion provided on the substrate to change an angle of divergence of a second incoming light beam to the optical element.    
     
     
         18 . The optical element according to  claim 17  wherein the first lens portion is provided to change the angle of divergence of the first incoming light beam in a first plane including an outgoing direction of the first incoming light beam having a maximum intensity, and the second lens portion is provided to change the angle of divergence of the second incoming light beam in a second plane including an outgoing direction of the second incoming light beam having a maximum intensity.  
     
     
         19 . The optical element according to  claim 18  wherein the first plane is orthogonal to the second plane.  
     
     
         20 . The optical element according to  claim 17  wherein the first lens portion and the second lens portion are unified.  
     
     
         21 . An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location, 
 the light source unit comprising: 
 a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and  
 a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.  
   
     
     
         22 . An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light beam reflected from the recording surface, the optical pickup device comprising: a light source unit package; and an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit package to the recording surface of the corresponding storage medium, 
 the light source unit package comprising: a light source unit, a branch optical element reflecting a light beam incident to the light source unit, in a predetermined direction, and a photodetector arranged at the light-receiving location and receiving the reflected light beam from the branch optical element, wherein the light source unit, the branch optical element and the photodetector are unified,    the light source unit comprising: 
 a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and  
 a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.  
   
     
     
         23 . An optical disk drive which performs recording, reproduction and erasing of information with a corresponding one of two or more optical disks of different types, the optical disk drive including: an optical pickup device and a reproduction signal processing unit performing reproduction of information based on a signal output by the optical pickup device, 
 the optical pickup device focusing a light beam on a recording surface of the corresponding optical disk and receiving a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location,    the light source unit comprising: 
 a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and  
 a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.  
   
     
     
         24 . An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light from the recording surface, the optical pickup device comprising: 
 a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;    an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element converting each light beam directed toward the object lens into a parallel light beam; and    a photodetector arranged at the light-receiving location and receiving the return light beam,    wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.    
     
     
         25 . The optical pickup device according to  claim 24  wherein each light beam focused with the object lens has a rim intensity that is inversely proportional to a wavelength of the light beam, the rim intensity indicating a ratio of an intensity in a pupil edge of the object lens to a maximum intensity in an entrance pupil of the object lens.  
     
     
         26 . The optical pickup device according to  claim 25  wherein the rim intensity is above 10% and below 70%.  
     
     
         27 . The optical pickup device according to  claim 24  wherein each light beam output from the plurality of light sources has an angle of divergence that is inversely proportional to a wavelength of the light beam.  
     
     
         28 . The optical pickup device according to  claim 24  wherein each light beam output from the plurality of light sources is a divergent light having an intensity distribution in an elliptical cross section of an outgoing direction of the light beam having a maximum intensity, and each light beam has an angle of divergence in a plane including a minor axis of the elliptical cross section, the angle of divergence being inversely proportional to a wavelength of the light beam.  
     
     
         29 . The optical pickup device according to  claim 24  wherein the optical system comprises an adjustment optical element which adjusts an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the optical element.  
     
     
         30 . The optical pickup device according to  claim 29  wherein the adjustment optical element is provided to select a specific wavelength of the light beam with which the angle of divergence is adjusted.  
     
     
         31 . The optical pickup device according to  claim 30  wherein the plurality of light sources includes a first light source which outputs a first light beam with a first wavelength and a second light source which outputs a second light beam with a second wavelength longer than the first wavelength.  
     
     
         32 . The optical pickup device according to  claim 31  wherein the adjustment optical element includes a first adjustment optical element and a second adjustment optical element which are mutually laminated and unified.  
     
     
         33 . The optical pickup device according to  claim 29  wherein the adjustment optical element is provided to change the magnitude of adjustment of the angle of divergence according to an applied voltage.  
     
     
         34 . The optical pickup device according to  claim 29  wherein the optical system includes a branch optical element which branches the return light beam, and the adjustment optical element is arranged between the branch optical element and the optical element.  
     
     
         35 . An optical disk drive which performs recording, reproduction and erasing of information with a corresponding one of two or more optical disks of different types, the optical disk drive including: an optical pickup device and a reproduction signal processing unit performing reproduction of information based on a signal output by the optical pickup device, the optical pickup device focusing a light beam on a recording surface of the corresponding optical disk and receiving a return light beam from the recording surface, the optical pickup device comprising: 
 a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;    an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element converting each light beam directed toward the object lens into a parallel light beam; and    a photodetector arranged at the light-receiving location and receiving the return light beam,    wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.    
     
     
         36 . An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light from the is recording surface, the optical pickup device comprising: 
 a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;    an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element changing an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the object lens; and    a photodetector arranged at the light-receiving location and receiving the return light beam.    
     
     
         37 . The optical pickup device according to  claim 36  wherein each light beam focused with the object lens has a rim intensity that is inversely proportional to a wavelength of the light beam, the rim intensity indicating a ratio of an intensity in a pupil edge of the object lens to a maximum intensity in an entrance pupil of the object lens.  
     
     
         38 . The optical pickup device according to  claim 37  wherein the rim intensity is above 10% and below 70%.  
     
     
         39 . The optical pickup device according to  claim 36  wherein each light beam output from the plurality of light sources has an angle of divergence that is inversely proportional to a wavelength of the light beam.  
     
     
         40 . The optical pickup device according to  claim 36  wherein each light beam output from the plurality of light sources is a divergent light having an intensity distribution in an elliptical cross section of an outgoing direction of the light beam having a maximum intensity, and each light beam has an angle of divergence in a plane including a minor axis of the elliptical cross section, the angle of divergence being inversely proportional to a wavelength of the light beam.  
     
     
         41 . The optical pickup device according to  claim 36  wherein the optical system comprises an adjustment optical element which adjusts an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the optical element.  
     
     
         42 . The optical pickup device according to  claim 41  wherein the adjustment optical element is provided to select a specific wavelength of the light beam with which the angle of divergence is adjusted.  
     
     
         43 . The optical pickup device according to  claim 42  wherein the plurality of light sources includes a first light source which outputs a first light beam with a first wavelength and a second light source which outputs a second light beam with a second wavelength longer than the first wavelength.  
     
     
         44 . The optical pickup device according to  claim 43  wherein the adjustment optical element includes a first adjustment optical element and a second adjustment optical element which are mutually laminated and unified.  
     
     
         45 . The optical pickup device according to  claim 41  wherein the adjustment optical element is provided to change the magnitude of adjustment of the angle of divergence according to an applied voltage.  
     
     
         46 . The optical pickup device according to  claim 41  wherein the optical system includes a branch optical element which branches the return light beam, and the adjustment optical element is arranged between the branch optical element and the optical element.  
     
     
         47 . The optical pickup device according to  claim 36  wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.  
     
     
         48 . A method of manufacture of an optical pickup device which has a plurality of light sources including a first light source and a second light source arranged in proximity, while leading each light beam which are outputs the angle of divergence of each light beam output from the first and the second light source from each light source including the optical element adjusted, respectively to the recording surface of the corresponding optical disk, comprising the steps of: 
 acquiring information about an outgoing direction of each light beam which is output from the first and second light sources passes through the optical element, respectively; and    compensating for the outgoing direction of each light beam by correcting a location of the optical element based on the acquired information about the outgoing direction.    
     
     
         49 . The method of manufacture according to  claim 48  further comprising the step of arranging the optical element for converting the light beam into a parallel light beam in an optical path of the light beam through the optical element.  
     
     
         50 . The method of manufacture according to  claim 48  wherein the first light source and the second light source are set in ON state to emit the light beams simultaneously in the acquisition step.  
     
     
         51 . The method of manufacture according to  claim 50  wherein the light beam output from first light source has an intensity different from an intensity of the light beam output from the second light source in the acquisition process.  
     
     
         52 . The method of manufacture according to  claim 50  further comprising the step of arranging a first filter which converts the light beam output from the first light source, or a second filter which converts the light beam output from the second light source.  
     
     
         53 . The method of manufacture according to  claim 48  wherein a photodetector which detects at the light-receiving location the light beam through the optical element is used in the acquisition step.  
     
     
         54 . The method of manufacture according to  claim 50  wherein the light beam output from the first light source is reflected by a branch optical element which reflects the light beam output from the second light source is arranged on the optical path of the light beam through the optical element.  
     
     
         55 . The method of manufacture according to  claim 48  wherein the first and the second light sources output each light beam one by one in the acquisition step.  
     
     
         56 . The method of manufacture according to  claim 48  further comprising the step of displaying the information about the outgoing direction acquired in the acquisition step.  
     
     
         57 . The method of manufacture according to  claim 48  wherein the optical element is a meniscus lens.