# Patent

## Title
Optical information recording/reproducing apparatus and objective optical system for the same

## Abstract

An objective optical system for an optical information recording/reproducing apparatus, at least one surface of the objective optical system being configured to be a phase shift surface having a phase shift structure, wherein: the phase shift surface has a first area contributing to converging first, second and third light beams onto recording surfaces of first, second and third optical discs, respectively; in the first area, the phase shift surface has at least two types of phase shift structures including a first phase shift structure having first steps and a second phase shift structure having second steps; the phase shift surface has a plurality of combinations of annular zones which satisfy a condition:

0.95<P1/P2<1.05  (1), and

the phase shift surface satisfies a following condition:

−3.00<Δφ1/Δφ2<−0.10  (2).

## Background
BACKGROUND OF THE INVENTION
The present invention relates to an objective optical system for an optical information recording/reproducing apparatus configured to record information to and/or reproduce information from a plurality of types of optical discs based on different standards, and to an optical information recording/reproducing apparatus on which such an objective optical system is mounted.
There exist various standards of optical discs, such as DVD (Digital Versatile Disc) and BD (Blu-ray Disc), differing in recording density, protective layer thickness, etc. Therefore, an objective optical system mounted on the optical information recording/reproducing apparatus is required to have a compatibility with a plurality of types of optical discs. In this case, the term “compatibility” means to guarantee realizing information recording and information reproducing without the need for replacement of components even when the optical disc being used is changed.
In order to have the compatibility with the plurality of types of optical discs based on the different standards, it is necessary to correct the relative spherical aberration which is caused depending on the difference in protective layer thickness between the optical discs and to form a suitable beam spot in accordance with the difference in recording density between the optical discs by changing the numerical aperture NA of the objective optical system. The optical information recording/reproducing apparatus is configured to use a plurality of types of laser beams having different wavelengths respectively for the plurality of recording densities of the optical discs. The optical information recording/reproducing apparatus uses, for example, light having the wavelength of approximately 790 nm (i.e., so-called near infrared laser light) for information recording or information reproducing for CD, light having the wavelength of approximately 660 nm (i.e., so-called red laser light) for information recording or information reproducing for DVD and light having the wavelength of approximately 405 nm (i.e., so-called blue laser light) for information recording or information reproducing for BD. Japanese Patent Provisional Publication No. 2009-199707A (hereafter, referred to as patent document #1) discloses a configuration of an optical information recording/reproducing apparatus having the compatibility with the three types of optical discs.
SUMMARY OF THE INVENTION
An objective lens disclosed in patent document #1 is provided with two types of steps respectively giving different additional optical path lengths to an incident light beam. One of the two types of steps (a first step) is configured such that the diffraction orders at which the diffraction efficiencies take the maximum values for the laser beams for BD/DVD/CD are 1st/0th/0th orders, and the other of the two types of steps (a second step) is configured such that the diffraction orders at which the diffraction efficiencies take the maximum values for the laser beams for BD/DVD/CD are 2nd/1st/1st orders. If the steps are designed such that an adequate spot light amount is secured for all the three types of light beams having the wavelengths for BD/DVD/CD, regarding the latter step the diffraction efficiency is high because in this case the phase shift is small for each of the laser beams having the wavelengths, while, regarding the former step, the diffraction efficiency is low because in this case the phase shift is large for each of the laser beams having the wavelengths. Therefore, the objective lens has a drawback that the overall light use efficiency is low.
The present invention is advantageous in that it provides an objective optical system and an optical information recording/reproducing apparatus which have the compatibility with a plurality of types of optical discs and are configured to suppress decrease of the light use efficiency.
According to an aspect of the invention, there is provided an objective optical system for an optical information recording/reproducing apparatus configured to record information to and/or reproduce information from three types of optical discs including first, second and third optical discs differing in recording density, by selectively using light beams having first, second and third wavelengths emitted from light sources. The objective optical system comprises at least an objective lens. When λ1 (unit: nm) represents the first wavelength, λ2 (unit: nm) represents the second wavelength and λ3 (unit: nm) represents the third wavelength, λ1, λ2 and λ3 are defined as: Δ1≈405, λ2≈660, and λ3≈790. When NA1 represents a numerical aperture required for the information recording or information reproducing for the first optical disc, NA2 represents a numerical aperture required for the information recording or information reproducing for the second optical disc, and NA3 represents a numerical aperture required for the information recording or information reproducing for the third optical disc, NA1, NA2 and NA3 satisfy a following relationship: NA1>NA2>NA3.
At least one surface of the objective optical system being configured to be a phase shift surface having a phase shift structure including a plurality of refractive surface zones concentrically divided so as to have steps giving different phase differences to an incident light beam at a boundary between adjacent ones of the plurality of refractive surface zones. The phase shift surface has a first area contributing to converging the first, second and third light beams onto recording surfaces of the first, second and third optical discs, respectively. The first area has an effective diameter larger than NA 0.3 at the first wavelength. In the first area, the phase shift surface has at least two types of phase shift structures including a first phase shift structure having first steps and a second phase shift structure having second steps.
When P1 (unit: mm) represents an arrangement interval defined in a direction perpendicular to an optical axis direction between two first steps which adjoin with respect to each other while sandwiching at least one second step, and P2 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two second steps which adjoin with respect to each other while sandwiching at least one first step and one of which is sandwiched between the two first steps, the phase shift surface is configured such that, in an area whose effective diameter is larger than NA 0.3 at the first wavelength in the first area, the phase shift surface has a plurality of combinations of annular zones which satisfy a condition (1):

0.95<P1/P2<1.05  (1)

where,
one of the two first steps arranged closer to the optical axis is defines as a first start step, and the other of the two first steps farther from the optical axis is defined as a first end step, when the first steps are continuously arranged in a direction perpendicular to the optical axis not to have the second steps therebetween, the arrangement interval P1 is determined by defining one of the continuously arranged first steps closest to the optical axis as the first start step and by defining the other of the continuously arranged first steps farthest from the optical axis as the first end step,
one of the two second steps arranged closer to the optical axis is defines as a second start step, and the other of the two second steps farther from the optical axis is defined as a second end step, and
when the second steps are continuously arranged in a direction perpendicular to the optical axis not to have the first steps therebetween, the arrangement interval P2 is determined by defining one of the continuously arranged second steps closest to the optical axis as the second start step and by defining the other of the continuously arranged second steps farthest from the optical axis as the second end step.
When Δφ1 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the first steps with respect to the light beam having the first wavelength in a case where the first steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ2 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the second steps with respect to the light beam having the first wavelength in a case where the second steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, in an area having an effective diameter larger than NA 0.3 at the first wavelength in the first area, the phase shift surface satisfies a following condition:

−3.00<Δφ1/Δφ2<−0.10  (2).

The objective optical system secures the compatibility with the first to third optical discs by giving the multiple optical effects by the plurality of types of phase shift structures formed in the first area, gives phase changes, which have approximately the same period and are in opposite directions, to the light beam having the first wavelength passed through the first step and the light beam having the first wavelength passed through the second step by satisfying both of the conditions (1) and (2), and thereby aligns the wavefront by cancelling the phase changes with respect to each other.
In at least one aspect, the phase shift surface may satisfy a following condition:

−1.30<Δφ1/Δφ2<−0.35  (3).

In at least one aspect, when φ1 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each first step and φ2 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each second step, the phase shift surface may satisfy following conditions:

2.2<φ1<2.8  (4), and

1.0<φ2<1.70  (5).

In at least one aspect, the phase shift surface may satisfy following conditions:

2.3<φ1<2.6  (6), and

1.1<φ2<1.5  (7).

In at least one aspect, when ΔOPD1 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each first step, and ΔOPD2 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each second step, the phase shift surface may satisfy following conditions:

1.1<ΔOPD1/λ1<1.4  (8), and

0.50<ΔOPD2/λ1<0.85  (9)

In at least one aspect, the phase shift surface may satisfy following conditions:

1.15<ΔOPD1/λ1<1.30  (10), and

0.55<ΔOPD2/λ1<0.75  (11).

In at least one aspect, when D1 (unit: μm) represents an absolute value of a height of the paraxially arranged first step in the optical axis direction, and D2 (unit: μm) represents an absolute value of the height of the paraxially arranged second step in the optical axis direction, the phase shift surface may satisfy following conditions:

0.70<D1<1.10  (12), and

0.30<D2<0.70  (13).

In at least one aspect, the phase shift surface may satisfy following conditions:

0.80<D1<0.95  (14), and

0.40<D2<0.55  (15).

In at least one aspect, when the at least two types of phase shift structures formed in the first area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:

φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ

where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik, represents a diffraction order at which the diffraction efficiency of an incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon), the first phase shift structure is a diffraction structure defined by a first optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are all 1st orders; and the second phase shift structure is a diffraction structure defined by a second optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are 1st order, 0-th order and 0-th order, respectively.
In at least one aspect, the phase shift surface may include a second area which is located outside the first area and which contributes to converging the light beams having the first and second wavelengths onto recording surfaces of the first and second optical discs, respectively and does not contribute to converging the light beam having the third wavelength. In the second area, the phase shift surface has at least two types of phase shift structures including a third phase shift structure having third steps and a fourth phase shift structure having fourth steps.
When P3 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two third steps which adjoin with respect to each other while sandwiching at least one fourth step, and P4 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two fourth steps which adjoin with respect to each other while sandwiching at least one third step and one of which is sandwiched between the two third steps, the phase shift surface may satisfy a following condition:

0.95<P3/P4<1.05  (16);

where,
one of the two third steps arranged closer to the optical axis is defines as a third start step, and the other of the two third steps farther from the optical axis is defined as a third end step,
when the third steps are continuously arranged in a direction perpendicular to the optical axis not to have the fourth steps therebetween, the arrangement interval P3 is determined by defining one of the continuously arranged third steps closest to the optical axis as the third start step and by defining the other of the continuously arranged third steps farthest from the optical axis as the third end step,
one of the two fourth steps arranged closer to the optical axis is defines as a fourth start step, and the other of the two fourth steps farther from the optical axis is defined as a fourth end step, and
when the fourth steps are continuously arranged in a direction perpendicular to the optical axis not to have the third steps therebetween, the arrangement interval P4 is determined by defining one of the continuously arranged fourth steps closest to the optical axis as the fourth start step and by defining the other of the continuously arranged fourth steps farthest from the optical axis as the fourth end step.
When Δφ3 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the third steps with respect to the light beam having the first wavelength in a case where the third steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ4 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the fourth steps with respect to the light beam having the first wavelength in a case where the fourth steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, the phase shift surface may satisfy a following condition:

−2.70<Δφ3/Δφ4<−0.05  (17).

In at least one aspect, the phase shift surface may satisfy a condition:

−1.05<Δφ3/Δφ4<−0.20  (18).

When φ3 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each third step and φ4 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each fourth step, the phase shift surface may satisfy following conditions:

2.1<φ3<2.8  (19), and

1.0<φ4<1.70  (20).

In at least one aspect, the phase shift surface may satisfy following conditions:

2.2<φ3<2.6  (21), and

1.1<φ4<1.5  (22).

When ΔOPD3 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each third step, and ΔOPD4 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each fourth step, the phase shift surface may satisfy following conditions:

1.05<ΔOPD3/λ1<1.4  (23), and

0.50<ΔOPD4/λ1<0.85  (24).

In at least one aspect, the phase shift surface may satisfy following conditions:

1.10<ΔOPD3/λ1<1.30  (25), and

0.55<ΔOPD4/λ1<0.75  (26).

When D3 (unit: mm) represents an absolute value of a height of the paraxially arranged third step in the optical axis direction, and D4 (unit: mm) represents an absolute value of a height of the paraxially arranged fourth step in the optical axis direction, the phase shift surface may satisfy following conditions:

0.85<D3<1.20  (27), and

0.45<D4<0.85  (28).

In at least one aspect, the phase shift surface may satisfy following conditions:

0.95<D3<1.10  (29), and

0.55<D4<0.75  (30).

When the at least two types of phase shift structures formed in the second area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:

φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ

where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik, represents a diffraction order at which the diffraction efficiency of the incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon),
the third phase shift structure is a diffraction structure defined by a third optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are all 1st orders; and the fourth phase shift structure is a diffraction structure defined by a fourth optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are 1st order and 0-th order, respectively.
In at least one aspect, the phase shift surface may have a third area which is located outside the second area and which is configured to contribute to converging the light beams having the first wavelength onto the recording surface of the first optical disc and not to contribute converging the light beams having the second and third wavelengths.
According to another aspect of the invention, there s provided an optical information recording/reproducing apparatus for recording information and/or reproducing information from three types of optical discs including first, second and third optical discs. The optical information recording/reproducing apparatus includes light sources that emit light beams having a first wave length, a second wavelength and a third wavelength, coupling lenses respectively converting degrees of divergence or convergence of the light beams having the first, second and third wavelengths emitted by the light sources, and one of the above described objective optical system.
The optical information recording/reproducing apparatus secures the compatibility with the first to third optical discs by giving the multiple optical effects by the plurality of types of phase shift structures formed in the first area, gives phase changes, which have approximately the same period and are in opposite directions, to the light beam having the first wavelength passed through the first step and the light beam having the first wavelength passed through the second step by satisfying both of the conditions (1) and (2), and thereby aligns the wavefront by cancelling the phase changes with respect to each other.



BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
FIG. 1 generally illustrates a configuration of an optical information recording/reproducing apparatus according to an embodiment of the invention.
FIGS. 2A and 2B generally illustrate a configuration of an objective lens according to the embodiment of the invention.
FIG. 3 illustrates a side cross section of the objective lens when an optical disc is used in the embodiment of the invention.
FIG. 4 is a developed view of a lens shape defined when an aspherical surface shape of a first surface of the objective lens is developed in a flat shape, and shows solely a shape of a phase shift structure formed in each area.
FIGS. 5A and 5B are explanatory illustrations for explaining arrangement intervals of the same type of steps formed in each area of the first surface of the objective lens.
FIGS. 6A to 6C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a first example of the invention.
FIGS. 7A to 7C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a second example of the invention.
FIGS. 8A to 8C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a third example of the invention.
FIGS. 9A to 9C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a fourth example of the invention.
FIGS. 10A to 10C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a fifth example of the invention.
FIGS. 11A to 11C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a sixth example of the invention.
FIGS. 12A to 12C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a seventh example of the invention.
FIGS. 13A to 13C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a eighth example of the invention.
FIGS. 14A to 14C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a ninth example of the invention.
FIGS. 15A to 15C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a tenth example of the invention.
FIGS. 16A to 16C are graphs illustrating wavefront aberrations caused when respective optical discs are used in the optical information recording/reproducing apparatus according to a eleventh example of the invention.



DETAILED DESCRIPTION OF THE EMBODIMENTS
Hereinafter, an optical system and an optical information recording/reproducing apparatus according to an embodiment of the invention are described with reference to the accompanying drawings. The optical information recording/reproducing apparatus according to the embodiment has the compatibility with three types of optical discs differing in protective layer thickness and recording density. Incidentally, in this specification, the “optical information recording/reproducing apparatuses” include apparatuses for both information reproducing and information recording, apparatuses exclusively for information reproducing, and apparatuses exclusively for information recording.
In the following, of the three types of optical discs, a high-recording density optical disc (e.g. BD) is referred to as an optical disc OD1, an optical disc (e.g., DVD) having the recording density lower than that of BD is referred to as an optical disc OD2, and an optical disc (e.g., CD) having the recording density lower than DVD is referred to as an optical disc OD3.
When the protective layer thicknesses of the optical discs OD1, OD2 and OD3 are defined as t1 (unit: mm), t2 (unit: mm) and t3 (unit: mm) respectively, concrete values of the protective layer thicknesses t1, t2 and t3 are as follows.

t1≈0.1

t2≈0.6

t3≈1.2

In consideration of errors with respective to design values due to individual differences or the temperature change, the protective layer thickness is defined by using the symbol “≈” in each expression.
When information recording or information reproducing is performed for the optical discs OD1, OD2 and OD3, it is required to change the numerical aperture NA so that a suitable beam spot can be formed depending on the difference in recording density between the optical discs OD1, OD2 and OD3. When the optimal design numerical apertures required for information recording or information reproducing for the optical discs OD1, OD2 and OD3 are defined as NA1, NA2 and NA3, respectively, the following relationship holds.

NA1>NA2>NA3

That is, when the optical disc OD1 having the highest recording density is used, it is required to form a beam spot smaller than that for the optical disc OD2 or OD3, and therefore the largest NA is required for the optical disc OD1. On the other hand, when the optical disc OD3 having the lowest recording density is used, it is required to form a beam spot larger than that for the optical disc OD1 or OD2, and therefore the smallest NA is required for the optical disc OD3.

For information recording or information reproducing for the optical discs OD1, OD2 and OD3 differing in recording density, laser beams having different wavelengths are used in the optical information recording/reproducing apparatus. Specifically, when the optical disc OD1 is used, a laser beam having a wavelength λ1 (unit: nm) is emitted from a light source to form the smallest beam spot on a recording surface of the optical disc OD1. When the optical disc OD2 is used, a laser beam having a wavelength λ2 (unit: nm) longer than the wavelength λ1 is emitted from a light source to form a beam spot larger than that for the optical disc OD1 on a recording surface of the optical disc OD2. When the optical disc OD3 is used, a laser beam having a wavelength λ3 (unit: nm) longer than the wavelength λ2 is emitted from a light source to form a beam spot larger than that for the optical disc D2 on a recording surface of the optical disc OD3. Numerical values of λ1, λ2 and λ3 are as follows.

λ1≈405

λ2≈660

λ3≈790

Each use wavelength is defined by using the symbol “≈” in each expression so that each use wavelength includes a minute wavelength range within which each use wavelength varies due to individual differences or the temperature change.
FIG. 1 generally illustrates a configuration of an optical information recording/reproducing apparatus 100 according to the embodiment. The optical information recording/reproducing apparatus 100 includes a light source 1A which emits a laser beam having the wavelength λ1, a light source 1B which emits a laser beam having the wavelength λ2, a light source 1C which emits a laser beam having the wavelength λ3, diffraction gratings 2A to 2C, coupling lenses 3A to 3C, beam splitters 41 and 42, half mirrors 5A to 5C, photoreceptors 6A to 6C, and an objective lens 10. In FIG. 1, a reference axis AX of the optical information recording/reproducing apparatus 100 is represented by a chain line. The laser beams having the wavelengths λ1, λ2 and λ3 are respectively represented by a solid line, a dashed line and a dotted line. In a normal state, an optical axis of the objective lens 10 coincides with the reference axis AX. However, there is a case where the optical axis of the objective lens 10 shifts from the reference axis AX for a tracking operation in which the objective lens 10 moves in a radial direction of the optical disc by a tracking mechanism.
In the optical information recording/reproducing apparatus 100, the required numerical apertures NAs of the objective lens 10 differ between the optical discs. Therefore, the optical information recording/reproducing apparatus 100 may be configured to use an aperture restriction element (not shown) for defining the beam diameter for each of the laser beams having the wavelengths λ1, λ2 and λ3.
The laser beams having the wavelengths λ1, λ2 and λ3 are emitted from the light sources 1A, 1B and 1C, when the optical discs OD1, OD2 and OD3 are used, respectively. The laser beams having the wavelengths λ1, λ2 and λ3 respectively pass through the diffraction gratings 2A, 2B and 2C, optical paths of the laser beams having the wavelengths λ1, λ2 and λ3 are bent by the half mirrors 5A, 5B and 5C, respectively, and then the laser beams having the wavelengths λ1, λ2 and λ3 enter the coupling lenses 3A, 3B and 3C, respectively. The coupling lenses 3A, 3B and 3C respectively convert the laser beams having the wavelengths λ1, λ2 and λ3 into collimated beams. Each of the collimated laser beams having the wavelengths λ1 and λ2 is incident on the objective lens 10 via the beam splitters 41 and 42. The collimated laser beam having the wavelengths λ3 is incident on the objective lens 10 via the beam splitter 42. The objective lens 10 converges the incident laser beams having the wavelengths λ1, λ2 and λ3 at positions in the vicinities of the recording surfaces of the optical discs OD1, OD2 and OD3, respectively. The converged laser beams form beam spots on the recording surfaces of the optical discs OD1, OD2 and OD3, respectively. The laser beams reflected from the recording surfaces of the optical discs OD1, OD2 and OD3 return along the same optical paths proceeding to the optical discs, and are detected by the photoreceptors 6A, 6B and 6C while passing through the half mirrors 5A, 5B and 5C. The photoreceptors 6A to 6C output detection signals to a signal processing circuit (which may have a known configuration). Based on the outputs from the photoreceptors 6A to 6C, the signal processing circuit detects a focusing error signal, a tracking error signal and a reproduction signal of the information recorded on the optical disc.
As described above, each of the laser beams emerging from the coupling lenses 3A to 3C is the collimated beam. That is, each of the coupling lenses 3A to 3C functions as a collimator lens. As described above, by employing a configuration in which the collimated beam is incident on the objective lens 10, it becomes possible to prevent occurrence of off-axis aberrations, such as a coma, even when the objective lens 10 shifts for the tracking operation. It should be noted that the scope of the present invention is not limited to the configuration where the collimated beam is incident on the objective lens 10, but the scope of the present invention encompasses a so-called finite optical system where a diverging laser beam having a low degree of divergence is incident on an optical component, such as an objective lens. By employing a finite optical system, it becomes possible to correct the spherical aberration which remains when the optical disc OD3 is used, and to easily secure an adequate working distance.
FIG. 2A is a front view of the objective lens 10, and FIG. 2B is a side cross sectional view of the objective lens 10. FIG. 3 is a side cross sectional view of the objective lens 10 when the optical disc OD1 (, OD2 or OD3) is used. As described above, the objective lens 10 is used for an optical head of the optical information recording/reproducing apparatus 100 having the compatibility with the plurality of types of optical discs OD1, OD2 and OD3 based on the different standards, and has the function of converging each laser beam emitted from a semiconductor laser being a light source onto the recording surface of each optical disc.
The objective lens 10 is a biconvex single element lens made of resin, and has a first surface 10a facing the beam splitter 42 and a second surface 10b facing the optical disc. Each of the first and second surfaces 10a and 10b of the objective lens 10 is an aspherical surface. A shape of an aspherical surface is expressed by a following equation:




  SAG
  =
  
    
      
        
          h
          2
        
        r
      
      
        1
        +
        
          
            1
            -
            
              
                (
                
                  1
                  +
                  κ
                
                )
              
              ⁢
              
                
                  (
                  
                    h
                    r
                  
                  )
                
                2
              
            
          
        
      
    
    +
    
      
        A
        4
      
      ⁢
      
        h
        4
      
    
    +
    
      
        A
        6
      
      ⁢
      
        h
        6
      
    
    +
    
      
        A
        8
      
      ⁢
      
        h
        8
      
    
    +
    ...
  




where, SAG (a sag amount) is a distance between a point on the aspherical surface at a height of h (unit: mm) from the optical axis and a plane tangential to the aspherical surface at the optical axis, 1/r represents a curvature of the aspherical surface on the optical axis (i.e., r is a curvature radius (unit: mm) of the aspherical surface on the optical axis), κ is a conical coefficient, and A4, A6, . . . represent aspherical coefficients larger than or equal to the fourth order. By forming each of the surfaces of the objective lens 10 to be an aspherical surface, it becomes possible to appropriately control the various aberrations, such as a spherical aberration and a coma.
As shown in FIG. 2A, the first surface 10a of the objective lens 10 includes a circular first area R1 centering at the optical axis, an annular second area R2 located outside the first area R1, and an annular third area R3 located outside the second area R2. Effective radiuses of the areas R1, R2 and R3 are defined based on NA3 (NA3 is larger than NA 0.3 at the wavelength λ1), NA2 and NA1, respectively. In the areas R1, R2 and R3, a phase shift structure is formed. The phase shift structure has a plurality of annular zones (refractive surface zones) which are concentrically formed about the optical axis and are divided by minute steps each of which extends in a direction parallel with the optical axis (see an enlarged view in FIG. 3). The phase shift structure may be formed only on the second surface 10b, or may be separated to be formed on both of the first and second surfaces 10a and 10b. It should be noted that, by providing the phase shift structure on the first surface 10a having a larger effective diameter as in the case of the embodiment, it becomes possible to design the phase shift structure such that the minimum annular zone width to be wide, and thereby it becomes possible to suppress loss of light amount at step portions of the annular zones. Furthermore, there are advantages that the phase shift structure is not worn even when the objective lens 10 is rubbed by a lens cleaner.
The phase shift structure may be formed on a separate optical element provided separately from the objective lens 10. The separate optical element may be arranged, for example, between the objective lens 10 and the beam splitter 42. In this case, the phase shift structure may be formed on one of surfaces of the separate optical element, or may be separated to be formed on both of the surfaces of the separate optical element. However, in consideration of the fact that aberrations would occur when optical axes of the objective lens and the separate optical element shift with respect to each other, it is preferable that the objective lens and the separate optical element shift together during the tracking operation.
Steps constituting the phase shift structure are provided such that a predetermined phase difference (i.e., a predetermined optical path length difference) is caused between a light beam passing through an inner side portion of a boundary of adjacent refractive surface zones and a light beam passing through an outer side portion of the boundary. In general, such a structure may be referred to as a diffraction structure. The phase shift structure configured such that the predetermined optical path length difference is an n-fold (n: integer) of a particular wavelength λα may be referred to as an n-th order diffraction structure having the blazed wavelength λα. The diffraction order of diffracted light which exhibits the maximum diffraction efficiency when a light beam having a particular wavelength λβ passes through the diffraction structure is determined as an integer m which is closest to a value determined by dividing, by the wavelength λβ, the optical path length difference given to the light beam having the wavelength λβ. In the following, the diffraction orders at which the laser beams having the wavelengths λ1, λ2 and λ3 respectively take the maximum diffraction efficiencies are referred to as “BD use diffraction order”, “DVD use diffraction order” and “CD use diffraction order”, respectively.
The diffraction structure (the annular zone structure) can be expressed by an i-th optical path difference function φik(h) for a k-th area, where each of i and k is an integer. The optical path difference function φik(h) is a function representing the functional capability of the objective lens 10 (a diffraction lens) in a form of an additional optical path length at the height h from the optical axis of the objective lens 10, and defines positions of steps in the phase shift structure. The optical path difference function φik(h) can be expressed by a following equation:

φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ

where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik, represents a diffraction order at which the diffraction efficiency of the incident laser beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the laser beam being used (incident thereon).
The phase shift structure in the areas R1 and R2 has a shape defined by combining at least two types of steps (i.e., at least two types of optical path difference functions). The phase shift structure in the areas R1 and R2 gives phase differences (optical path length differences) different from each other, to the incident light beam, by combining the at least two types of steps (optical path difference functions). As a result, multiple optical effects can be given to the incident light beam.
In the area R1, a phase shift structure (hereafter, referred to as “a phase shift structure r1” for convenience of explanation) defined by combining a first phase shift structure having first steps and a second phase shift structure having second steps is formed. The phase shift structure r1 contributes to convergence for all of the laser beams having the wavelengths λ1, λ2 and λ3. That is, the phase shift structure r1 is configured to converge the laser beam having the wavelength λ1 onto the recording surface of the optical disc OD1, to converge the laser beam having the wavelength λ2 onto the recording surface of the optical disc OD2, and to converge the laser beam having the wavelength λ3 onto the recording surface of the optical disc OD3.
FIG. 4 is a developed view of a lens shape defined when the aspherical surface shape of the first surface 10a of the objective lens 10 is developed in a flat shape, and shows solely the shape of the phase shift structure formed in the areas R1 to R3. As shown in FIG. 4, in the area R1, the first step defining a projected annular zone and the second step defining the recessed shape are formed alternately.
When P1 (unit: mm) represents an arrangement interval (see “P” in the enlarged view in FIG. 3) defined in a direction perpendicular to the optical axis direction between two first steps which adjoin with respect to each other while sandwiching at least one second step therebetween, and P2 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two second steps which adjoin with respect to each other while sandwiching at least one first step therebetween, i.e., two second steps one of which is sandwiched between the above described two first steps, the phase shift structure r1 is configured such that, in an area whose effective diameter is larger than NA 0.3 at the wavelength λ1 in the area R1, the phase shift structure r1 has a plurality of combinations of annular zones which satisfy a following condition:

0.95<P1/P2<1.05  (1).

One of the two first steps arranged to have the arrangement interval P1 closer to the optical axis is defines as a first start step, and the other of the two first steps farther from the optical axis is defined as a first end step. One of the two second steps arranged to have the arrangement interval P2 closer to the optical axis is defines as a second start step, and the other of the two second steps farther from the optical axis is defined as a second end step. When the first steps are continuously arranged in a direction perpendicular to the optical axis not to have the second step therebetween, the interval arrangement P1 is determined by defining one of the continuously arranged first steps closest to the optical axis as the first start step and by defining the other of the continuously arranged first steps farthest from the optical axis as the first end step. When the second steps are continuously arranged in a direction perpendicular to the optical axis not to have the first step therebetween, the arrangement interval P2 is determined by defining one of the continuously arranged second steps closest to the optical axis as the second start step and by defining the other of the continuously arranged second steps farthest from the optical axis as the second end step.
The arrangement intervals P1 and P2 will now be explained with reference to FIGS. 5A and 5B. Each of FIGS. 5A and 5B is illustrated such that the left side is closer to the optical axis. FIG. 5A shows an example of a step structure where the first step and the second step appear alternately. As shown in FIG. 5A, an interval between the first start step and the first end step adjoining with respect to each other while sandwiching the second start step is the arrangement interval P1, and an interval between the second start step and the second end step adjoining with respect to each other while sandwiching the first end step is the arrangement interval P2. FIG. 5B shows an example of a step structure where the first steps X and Y are continuously arranged without sandwiching the second step. As shown in FIG. 5B, in this case, the first step X of the first steps X and Y closer to the optical axis is the first start step, and the first end step is not the step Y but the first step Z which is positioned next to the second end step while sandwiching the second end step between the first steps Y and Z. That is, an arrangement interval between the first steps X and Z is the arrangement interval P1. The arrangement interval P2 is an interval between the second start step and the second end step arranged to adjoin with respect to each other while sandwiching the continuously arranged first steps X and Y therebetween.
When Δφ1 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the first step with respect to the laser beam having the wavelength λ1 in the case where the first step gives an additional optical path length to the laser beam having the wavelength λ1 in the direction indicated by an arrow A in FIG. 2, and Δφ2 (unit: radian) represents a difference between 2π and an absolute vale of the phase change caused by the second step with respect to the laser beam having the wavelength λ1 in the case where the second step gives an additional optical path length to the laser beam having the wavelength λ1 in the direction indicated by an arrow B in FIG. 2 which is opposite to the direction indicated by the arrow A, the phase shift structure r1 satisfies a following condition (2) at least in an area having an effective diameter larger than NA 0.3 at the wavelength λ1 in the area R1.

−3.00<Δφ1/Δφ2<−0.10  (2)

The phase shift structure r1 secures the compatibility with the optical discs OD1 to OD3 by giving the multiple optical effects by the first and second steps to the laser beams having the wavelengths λ1, λ2 and λ3, gives phase changes, which have approximately the same period and are in opposite directions, to the laser beam having the wavelength λ1 passed through the first step and the laser beam having the wavelength λ1 passed through the second step by satisfying both of the conditions (1) and (2), and thereby aligns the wavefront by cancelling the phase changes with respect to each other. That is, the phase shift structure r1 is configured to effectively suppress decrease of the light use efficiency due to the phase shift by cancelling the phase shift caused by the phase shift structure with the different phase change, for the laser beam having the wavelength λ1 for which a particularly high light use efficiency is required.
When at least one of the conditions (1) and (2) is not satisfied, the cancelling effect between the phase change given to the laser beam having the wavelength λ1 passed through the first step and the phase change given to the laser beam having the wavelength λ1 passed through the second step is small, and therefore a large phase shift remains and it becomes impossible to effectively suppress decrease of the light use efficiency due to the phase shift.
In order to more effectively suppress decrease of the light use efficiency of the laser beam having the wavelength λ1 by enhancing the cancelling effect between the phase change given to the laser beam having the wavelength λ1 passed through the first step and the phase change given to the laser beam having the wavelength λ1 passed through the second step, the phase shift structure r1 may be configured to satisfy a following condition:

−1.30<Δφ1/Δφ2<−0.35  (3).

When φ1 (unit: πradian) represents an absolute value of the phase difference given to the laser beam having the wavelength λ1 by the first step and φ2 (unit: πradian) represents an absolute value of the phase difference given to the laser beam having the wavelength λ1 by the second step, the phase shift structure r1 may be configured to satisfy following conditions (4) and (5).

2.2<φ1<2.8  (4)

1.0<φ2<1.70  (5)

When both of the conditions (4) and (5) are satisfied, the wavefront is aligned by the cancelling effect between the phase difference given to the laser beam having the wavelength λ1 by the first step and the phase difference given to the laser beam having the wavelength λ1 by the second step. Therefore, decrease of the light use efficiency of the laser beam having the wavelength λ1 can be suppressed. Regarding the condition (4), the upper limit is determined to secure the light use efficiency larger than or equal to 70% for the laser beam having the wavelength λ1, and the lower limit is determined to secure the light use efficiency larger than or equal to 40% for the laser beam having the wavelength λ3. Regarding the condition (5), the upper and lower limits are determined to secure the light use efficiency larger than or equal to 50% for the laser beam having the wavelength λ2. Furthermore, when both of the conditions (4) and (5) are satisfied, the height of each of the first and second steps is low, which eases the metal mold processing and the molding. Consequently, loss of light amount by a manufacturing error such as a transfer failure can be effectively suppressed.
When at least one of the conditions (4) and (5) is not satisfied, the cancelling effect for the phase differences given by the first and second steps is small, and therefore the light use efficiency of the laser beams having the wavelengths λ2 and λ3 decreases extremely. Furthermore, when φ1 gets larger than the upper limit of the condition (4), the height of the first step becomes high. When φ2 gets smaller than the lower limit of the condition (5), the height of the second step becomes high. In either case, a manufacturing error such as a transfer failure is easy to occur. Therefore, there is a concern that loss of light amount by a manufacturing error is caused largely. The loss of light amount of this type does not contribute to convergence of light onto the recording surface of the optical disc OD1, and appears as flare light near the spot, which causes deterioration of a reproducing property.
In order to more effectively suppress decrease of the light use efficiency of the laser beam having the wavelength λ1 by enhancing the cancelling effect between the phase difference given to the laser beam having the wavelength λ1 by the first step and the phase difference given to the laser beam having the wavelength λ1 by the second step, the phase shift structure r1 may be configured to satisfy following conditions (6) and (7).

2.3<φ1<2.6  (6)

1.1<φ2<1.5  (7)

By satisfying the condition (6), the light use efficiency for each of the laser beam having the wavelength of λ1 and the laser beam having the wavelength λ3 can be improved by approximately 10%. By satisfying the condition (7), the light use efficiency for the laser beam having the wavelength λ2 can be improved by approximately 10%.

When ΔOPD1 (unit: μm) represents an absolute value of the optical path length difference given to the laser beam having the wavelength λ1 by the first step, and ΔOPD2 (unit: μm) represents an absolute value of the optical path length difference given to the laser beam having the wavelength λ1 by the second step, the phase shift structure r1 may be configured to satisfy following conditions (8) and (9) in place of the conditions (4) and (5).

1.1<ΔOPD1/λ1<1.4  (8)

0.50<ΔOPD2/λ1<0.85  (9)

The phase shift structure r1 may be configured to satisfy following conditions (10) and (11) in place of the conditions (6) and (7).

1.15<ΔOPD1/λ1<1.30  (10)

0.55<ΔOPD2/λ1<0.75  (11)

When D1 (unit: μm) represents an absolute value of the height (see a reference symbol “D” in the enlarged view in FIG. 3) of the paraxially arranged first step in the optical axis direction, and D2 (unit: μm) represents an absolute value of the height of the paraxially arranged second step in the optical axis direction, the phase shift structure r1 may be configured to satisfy following conditions (12) and (13) in place of the conditions (4) and (5).

0.70<D1<1.10  (12)

0.30<D2<0.70  (13)

The phase shift structure r1 may be configured to satisfy following conditions (14) and (15) in place of the conditions (6) and (7).

0.80<D1<0.95  (14)

0.40<D2<0.55  (15)

The first phase shift structure can be represented as a diffraction structure defined by a first optical path difference function whose BD use diffraction order, DVD use diffraction order and CD use diffraction order are all the 1st orders. In addition, the second phase shift structure can be represented as a diffraction structure defined by a second optical path difference function whose BD use diffraction order, DVD use diffraction order and CD use diffraction order are the 1st order, the 0-th order and the 0-th order, respectively. By defining each of the use diffraction orders to be a low order, it becomes possible to set the height of each of the first and second steps to be low, which eases the metal mold processing and the molding. As a result, loss of light amount due to a manufacturing error, such as a transfer failure, can be effectively suppressed.
In the area R2, a phase shift structure (hereafter, referred to as “a phase shift structure r2” for convenience of explanation) defined by combining a third phase shift structure having third steps and a fourth phase shift structure having fourth steps is formed. The phase shift structure r2 contributes only to convergence of the laser beams having the wavelength λ1 and λ2. That is, the phase shift structure r2 is configured to converge the laser beam having the wavelength λ1 onto the recording surface of the optical disc OD1, to converge the laser beam having the wavelength λ2 onto the recording surface of the optical disc OD2, and not to converge the laser beam having the wavelength λ3 onto the recording surfaces of any of the optical discs OD1 to OD3. As shown in FIG. 4, in the area R2, generally the third step defining a projected annular zone and the fourth step defining a recessed annular zone are alternately arranged.
When P3 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two third steps which adjoin with respect to each other while sandwiching at least one fourth step, and P4 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two fourth steps which adjoin with respect to each other while sandwiching at least one third step, i.e., two fourth steps one of which is sandwiched between the above described two third steps, the phase shift structure r2 is configured to have a plurality of combinations of annular zones which satisfy a following condition:

0.95<P3/P4<1.05  (16).

One of the two third steps arranged to have the arrangement interval P3 closer to the optical axis is defines as a third start step, and the other of the two third steps farther from the optical axis is defined as a third end step. One of the two fourth steps arranged to have the arrangement interval P4 closer to the optical axis is defines as a fourth start step, and the other of the two fourth steps farther from the optical axis is defined as a fourth end step. When the third steps are continuously arranged in a direction perpendicular to the optical axis not to have the fourth step therebetween, the arrangement interval P3 is determined by defining one of the continuously arranged third steps closest to the optical axis as the third start step and by defining the other of the continuously arranged third step farthest from the optical axis as the third end step. When the fourth steps are continuously arranged in a direction perpendicular to the optical axis not to have the third step therebetween, the arrangement interval P4 is determined by defining one of the continuously arranged fourth steps closest to the optical axis as the fourth start step and by defining the other of the continuously arranged fourth step farthest from the optical axis as the fourth end step.
When Δφ3 (unit: radian) is represents a difference between 2π and an absolute value of the phase change caused by the third step with respect to the laser beam having the wavelength λ1 in the case where the third step gives an additional optical path length to the laser beam having the wavelength λ1 in the direction indicated by the arrow A in FIG. 2, and Δφ4 (unit: radian) represents a difference between 2π and an absolute value of the phase change caused by the fourth step with respect to the laser beam having the wavelength λ1 when the fourth step gives an additional optical path length to the laser beam having the wavelength λ1 in the direction indicated by an arrow B in FIG. 2 which is opposite to the direction indicated by the arrow A, the phase shift structure r2 satisfies a following condition:

−2.70<Δφ3/Δφ4<−0.05  (17).

The phase shift structure r2 secures the compatibility with the optical discs OD1 and OD2 by giving the multiple optical effects by the third and fourth steps to the laser beams having the wavelengths λ1 and λ2, gives phase changes, which have approximately the same period and are in opposite directions, to the laser beam having the wavelength λ1 passed through the third step and the laser beam having the wavelength λ1 passed through the fourth step by satisfying both of the conditions (16) and (17), and thereby aligns the wavefront by cancelling the phase changes with respect to each other. That is, the phase shift structure r2 is configured to effectively suppress decrease of the light use efficiency due to the phase shift by cancelling the phase shift caused by the phase shift structure with the different phase change, for the laser beam having the wavelength λ1 for which a particularly high light use efficiency is required.
When at least one of the conditions (16) and (17) is not satisfied, the cancelling effect between the phase change given to the laser beam having the wavelength λ1 passed through the third step and the phase change given to the laser beam having the wavelength λ1 passed through the fourth step is small, and therefore a large phase shift remains and it becomes impossible to effectively suppress decrease of the light use efficiency due to the phase shift.
In order to more effectively suppress decrease of the light use efficiency by enhancing the cancelling effect between the phase change given to the laser beam having the wavelength λ1 passed through the third step and the phase change given to the laser beam having the wavelength λ1 passed through the fourth step, the phase shift structure r2 may be configured to satisfy a following condition:

−1.05<Δφ3/Δφ4<−0.20  (18).

When φ3 (unit: πradian) represents an absolute value of the phase difference given to the laser beam having the wavelength λ1 by the third step and φ4 (unit: πradian) represents an absolute value of the phase difference given to the laser beam having the wavelength λ1 by the fourth step, the phase shift structure r2 may be configured to satisfy following conditions (19) and (20).

2.1<φ3<2.8  (19)

1.0<φ4<1.70  (20)

When both of the conditions (19) and (20) are satisfied, the wavefront is aligned by the cancelling effect between the phase difference given to the laser beam having the wavelength λ1 by the third step and the phase difference given to the laser beam having the wavelength λ1 by the fourth step. Regarding the condition (19), the upper limit is determined to secure the light use efficiency larger than or equal to 70% for the laser beam having the wavelength λ1, and the lower limit is determined to secure the light use efficiency larger than or equal to 50% for the laser beam having the wavelength λ2. Regarding the condition (20), the upper and lower limits are determined to secure the light use efficiency larger than or equal to 50% for the laser beam having the wavelength λ2. Therefore, decrease of the light use efficiency of the laser beam having the wavelength λ1 can be suppressed. Furthermore, when both of the conditions (19) and (20) are satisfied, the height of each of the third and fourth steps is low, which eases the metal mold processing and the molding. Consequently, loss of light amount by a manufacturing error such as a transfer failure can be effectively suppressed.
When at least one of the conditions (19) and (20) is not satisfied, the cancelling effect for the phase differences given by the third and fourth steps is small, and therefore the light use efficiency of the laser beam having the wavelength λ2 decreases extremely. Furthermore, when φ3 gets larger than the upper limit of the condition (19), the height of the third step becomes high. When φ4 gets smaller than the lower limit of the condition (20), the height of the fourth step becomes high. In either case, a manufacturing error such as a transfer failure is easy to occur. Therefore, there is a concern that loss of light amount by a manufacturing error is caused largely. The loss of light amount of this type does not contribute to convergence of light onto the recording surface of the optical disc OD1, and appears as flare light near the spot, which causes deterioration of a reproducing property.
In order to more effectively suppress decrease of the light use efficiency of the laser beam having the wavelength λ1 by enhancing the cancelling effect between the phase difference given to the laser beam having the wavelength λ1 by the third step and the phase difference given to the laser beam having the wavelength λ1 by the fourth step, the phase shift structure r2 may be configured to satisfy following conditions (21) and (22).

2.2<φ3<2.6  (21)

1.1<φ4<1.5  (22)

By satisfying the condition (21), the light use efficiency for each of the laser beam having the wavelength of λ1 and the laser beam having the wavelength λ3 can be improved by approximately 10%. By satisfying the condition (22), the light use efficiency for the laser beam having the wavelength λ2 can be improved by approximately 10%.
When ΔOPD3 (unit: μm) represents an absolute value of the optical path length difference given to the laser beam having the wavelength λ1 by the third step, and ΔOPD4 (unit: μm) represents an absolute value of the optical path length difference given to the laser beam having the wavelength λ1 by the fourth step, the phase shift structure r2 may be configured to satisfy following conditions (23) and (24) in place of the conditions (19) and (20).

1.05<ΔOPD3/λ1<1.4  (23)

0.50<ΔOPD4/λ1<0.85  (24)

The phase shift structure r2 may be configured to satisfy following conditions (25) and (26) in place of the conditions (21) and (22).

1.10<ΔOPD3/λ1<1.30  (25)

0.55<ΔOPD4/λ1<0.75  (26)

When D3 (unit: mm) represents an absolute value of the height of the paraxially arranged third step in the optical axis direction, and D4 (unit: mm) represents an absolute value of the height of the paraxially arranged fourth step in the optical axis direction, the phase shift structure r2 may be configured to satisfy following conditions (27) and (28) in place of the conditions (19) and (20).

0.85<D3<1.20  (27)

0.45<D4<0.85  (28)

The phase shift structure r2 may be configured to satisfy following conditions (29) and (30) in place of the conditions (21) and (22).

0.95<D3<1.10  (29)

0.55<D4<0.75  (30)

The third phase shift structure can be represented as a diffraction structure defined by a third optical path difference function whose BD use diffraction order and DVD use diffraction order are all the 1st orders. In addition, the fourth phase shift structure can be represented as a diffraction structure defined by a fourth optical path difference function whose BD use diffraction order and DVD use diffraction order are the 1st order and the 0-th order, respectively. By defining each of the use diffraction orders to be a low order, it becomes possible to set the height of each of the third and fourth steps to be low, which eases the metal mold processing and the molding. As a result, loss of light amount due to a manufacturing error, such as a transfer error, can be effectively suppressed.
The area R3 contributes only to convergence of the laser beam having the wavelength λ1. That is, the area R3 is configured to converge the laser beam having the wavelength λ1 onto the recording surface of the optical disc OD1 and not converge the laser beams having the wavelengths λ2 and λ3 onto any of the optical discs OD1 to OD3. As shown in FIG. 4, one type of sawtooth-like annular zone structure is formed in the area R3.
In the following, eleven concrete examples (first to eleventh examples) of the optical information recording/reproducing apparatus 100 on which the objective lens 10 is mounted are explained. The optical information recording/reproducing apparatus 100 according each of the first to eleventh examples has the configuration generally illustrated in FIG. 1. The objective lens 10 according to each of the first to eleventh examples has the configuration generally illustrated in FIGS. 2 and 3. Actual differences between the optical elements produced in accordance with the numerical values of the first to eleventh examples are minute in the scaling of the accompanying drawings. Therefore, the whole configurations of the optical information recording/reproducing apparatus 100 according to the first to eleventh examples are explained with reference to FIG. 1, and the configurations of the objective lens 10 according to the first to eleventh examples are explained with reference to FIG. 3.
First Example
Hereafter, a first example of the optical information recording/reproducing apparatus 100 is described. The specifications of the objective lens 10 mounted on the optical information recording/reproducing apparatus 100 according to the first example are indicated in the following Table 1. Specifically, Table 1 shows the design wavelength (use wavelength) (unit: nm), the focal length (unit: mm), NA and the magnification of the objective lens 10. Various definitions regarding Tables and drawings in the first example are also applied to Tables and drawings in the other examples.












TABLE 1








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.765
1.990
2.053


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00









As shown by the magnification in Table 1, in the optical information recording/reproducing apparatus 100 according to the first example, each of the laser beams used for the respective optical discs OD1 to OD3 is incident on the objective lens 10 as a collimated beam. Therefore, it is possible to prevent the off-axis aberrations from occurring when the objective lens 10 is shifted for a tracking operation.
The following Table 2 shows the numeral configuration of the optical information recording/reproducing apparatus 100 defined when each of the optical discs OD1 to DO3 is used.












TABLE 2







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.110
1.880


Objective Lens


1-2
1.106


1-3
0.999


2
−2.938
0.673
0.613
0.305


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53635

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4









In Table 2, the surface numbers 1-1, 1-2 and 103 represent the areas R1, R2 and R3 of the first surface 10a of the objective lens 10, respectively. The surface number 2 represents the second surface 10b of the objective lens 10. The surface number 3 represents the protective layer of the targeted optical disc. In Table 2, “r” denotes the curvature radius (unit: mm) of each optical surface, “d(405 nm)” denotes the thickness of an optical component or the distance (unit: mm) from each optical surface to the next optical surface defined when the optical disc OD1 is used, “d(660 nm)” denotes the thickness of an optical component or the distance (unit: mm) from each optical surface to the next optical surface defined when the optical disc OD2 is used, and “d(790 nm)” denotes the thickness of an optical component or the distance (unit: mm) from each optical surface to the next optical surface defined when the optical disc OD3 is used. “n (406 nm)”, “n (660 nm)” and “n (790 nm)” represent the refractive indexes at the respective wavelengths indicated in the parentheses.
Each of the first surface 10a (surface numbers 1-1. 1-2 and 1-3) and the second surface 10b of the objective lens 10 are aspherical surfaces. Each of the aspherical surfaces is designed to be most suitable for information recording or information reproducing for the optical discs OD1 to OD3. The following Table 3 shows the conical coefficients κ and aspherical coefficients A4, A6 . . . of each aspherical surface. In each of Tables, the notation “E” means the power of 10 with an exponent specified by the number to the right of E (e.g. “E-04” means “×10−4”).











TABLE 3






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
2.87100E−02
−9.85200E−02 
−7.50430E−02
 3.51110E−01


A6
1.16600E−02
2.10900E−01
 7.83770E−02
−5.61660E−01


A8
−8.80800E−04 
−9.51300E−02 
−2.77640E−02
 9.15020E−01


A10
−8.91600E−05 
9.89250E−03
 3.02130E−02
−1.08740E+00


A12
1.96460E−04
2.33830E−03
−2.48190E−02
 8.39010E−01


A14


 1.05710E−02
−3.94180E−01


A16


−1.80380E−03
 1.02480E−01


A18



−1.12240E−02


A20


A22


A24









Each of the areas R1 to R3 has a unique phase shift structure (diffraction structure). Coefficients of optical path difference functions for defining the phase shift structure in each of the areas on the first surface 10a and the use diffraction orders are shown in Tables 4 and 5. “1-1” in each of Tables 4 and 5 represents BD use diffraction order/DVD use diffraction order/CD use diffraction order (1/1/1 in the first phase shift structure, 1/0/0 in the second phase shift structure) in the first and second phase shift structures constituting the phase shift structure r1 in the area R1, and the optical path difference function coefficients of the first and second phase shift structures. “1-2” in each of the Tables 4 and 5 represents BD use diffraction order/DVD use diffraction order/CD use diffraction order (1/1/- in the third phase shift structure, 1/0/- in the fourth phase shift structure) in the third and fourth phase shift structures constituting the phase shift structure r2 in the area R2, and the optical path difference function coefficients of the third and fourth phase shift structures. “1-3” in Table 5 represents the BD use diffraction order (2/-/-) in the phase shift structure formed in the area R3, and the optical path difference coefficients of the phase shift structure.










TABLE 4





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
5.76530E+01
5.89870E+01
4.49720E+01


P4
−1.41280E+01 
−1.20860E+02 
−8.67570E+01 


P6
5.21900E+00
1.86980E+02
5.43030E+01


P8
−2.88500E+00 
−1.04760E+02 
−1.14172E+01 


P10
9.07300E−03
1.94830E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 5







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.69430E+01
−3.60230E+01



P4
−7.43100E+00
−7.73070E+01



P6
 1.62700E+00
 1.21400E+02



P8
−9.77900E−01
−6.85160E+01



P10
−1.54900E−01
 1.27460E+01



P12
 0.00000E+00
 0.00000E+00










The concrete configuration of the phase shift structure formed in the areas R1 to R3 are shown in the following Tables 6A to 6C. In Tables 6A to 6C, the number of each annular zone constituting the phase shift structure is assigned in the order from the optical axis. The annular zone number 60 in FIG. 6A is followed by the annular one number 61 in Table 6B, and the annular zone number 120 in Table 6B is followed by the annular zone number 121 in Table 6C. The width of each annular zone is defined by an “annular zone start position” and an “annular zone end position” in Tables 6A to 6C. In Tables 6A to 6C, phase differences φ1 to φ4, optical path length differences ΔOPD1/λ1 to ΔOPD4/λ1 and the heights of steps D1 to D4 between the annular zones (steps), and, the phase difference, the optical path length difference and the height of each step in the phase shift structure in the area R3 are also shown.










TABLE 6A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First
0
0.000
0.071











Area
1
0.071
0.126

1.39

0.69

0.50






2
0.126
0.163
2.46

1.23

0.89


0.092




3
0.163
0.194

1.39

0.69

0.50
0.068

0.734



4
0.194
0.220
2.46

1.23

0.89


0.078




5
0.220
0.240

1.39

0.69

0.50
0.069

0.888



6
0.240
0.263

1.39

0.69

0.50






7
0.263
0.283
2.46

1.23

0.89


0.042




8
0.283
0.301

1.39

0.69

0.50
0.039

0.919



9
0.301
0.319
2.46

1.23

0.89


0.051




10
0.319
0.334

1.39

0.69

0.50
0.048

0.946



11
0.334
0.350

1.39

0.69

0.50






12
0.350
0.365
2.46

1.23

0.89


0.031




13
0.365
0.380

1.39

0.69

0.50
0.030

0.963



14
0.380
0.394
2.46

1.23

0.89


0.029




15
0.394
0.408

1.39

0.69

0.50
0.028

0.967



16
0.408
0.421
2.46

1.23

0.89


0.038




17
0.421
0.432

1.39

0.69

0.50
0.037

0.970



18
0.432
0.445

1.39

0.69

0.50






19
0.445
0.457
2.46

1.23

0.89


0.025




20
0.457
0.469

1.39

0.69

0.50
0.024

0.971



21
0.469
0.481
2.46

1.23

0.89


0.024




22
0.481
0.492

1.39

0.69

0.50
0.023

0.978



23
0.492
0.503
2.46

1.23

0.89


0.032




24
0.503
0.513

1.39

0.69

0.50
0.031

0.977



25
0.513
0.523

1.39

0.69

0.50






26
0.523
0.534
2.46

1.23

0.89


0.021




27
0.534
0.544

1.39

0.69

0.50
0.021

0.983



28
0.544
0.554
2.46

1.23

0.89


0.020




29
0.554
0.564

1.39

0.69

0.50
0.020

0.980



30
0.564
0.574
2.46

1.23

0.89


0.020




31
0.574
0.583

1.39

0.69

0.50
0.019

0.981



32
0.583
0.593
2.46

1.23

0.89


0.019




33
0.593
0.602

1.39

0.69

0.50
0.019

0.986



34
0.602
0.611
2.46

1.23

0.89


0.026




35
0.611
0.619

1.39

0.69

0.50
0.026

0.985



36
0.619
0.628

1.39

0.69

0.50






37
0.628
0.637
2.46

1.23

0.89


0.018




38
0.637
0.646

1.39

0.69

0.50
0.018

0.988



39
0.646
0.654
2.46

1.23

0.89


0.017




40
0.654
0.663

1.39

0.69

0.50
0.017

0.989



41
0.663
0.671
2.46

1.23

0.89


0.017




42
0.671
0.679

1.39

0.69

0.50
0.017

0.988



43
0.679
0.687
2.46

1.23

0.89


0.016




44
0.687
0.695

1.39

0.69

0.50
0.016

0.987



45
0.695
0.703
2.46

1.23

0.89


0.016




46
0.703
0.711

1.39

0.69

0.50
0.016

0.988



47
0.711
0.719
2.46

1.23

0.89


0.016




48
0.719
0.727

1.39

0.69

0.50
0.016

0.990



49
0.727
0.735
2.46

1.23

0.89


0.015




50
0.735
0.742

1.39

0.69

0.50
0.015

0.992



51
0.742
0.750
2.46

1.23

0.89


0.015




52
0.750
0.757

1.39

0.69

0.50
0.015

0.992



53
0.757
0.764
2.46

1.23

0.89


0.015




54
0.764
0.772

1.39

0.69

0.50
0.015

0.991



55
0.772
0.779
2.46

1.23

0.89


0.015




56
0.779
0.786

1.39

0.69

0.50
0.014

0.990



57
0.786
0.793
2.46

1.23

0.89


0.014




58
0.793
0.800

1.39

0.69

0.50
0.014

0.990



59
0.800
0.807
2.46

1.23

0.89


0.014




60
0.807
0.814

1.39

0.69

0.50
0.014

0.992




























TABLE 6B







First Area
61
0.814
0.821
2.46

1.23

0.89


0.014




62
0.821
0.828

1.39

0.69

0.50
0.014

0.993



63
0.828
0.835
2.46

1.23

0.89


0.014




64
0.835
0.842

1.39

0.69

0.50
0.014

0.993



65
0.842
0.848
2.46

1.23

0.89


0.013




66
0.848
0.855

1.39

0.69

0.50
0.013

0.992



67
0.855
0.861
2.46

1.23

0.89


0.013




68
0.861
0.868

1.39

0.69

0.50
0.013

0.990



69
0.868
0.875
2.46

1.23

0.89







70
0.875
0.882
2.46

1.23

0.89


0.020




71
0.882
0.888

1.39

0.69

0.50
0.020

0.994



72
0.888
0.895
2.46

1.23

0.89


0.013




73
0.895
0.901

1.39

0.69

0.50
0.013

0.992



74
0.901
0.907
2.46

1.23

0.89


0.013




75
0.907
0.913

1.39

0.69

0.50
0.013

0.995



76
0.913
0.920
2.46

1.23

0.89


0.012




77
0.920
0.926

1.39

0.69

0.50
0.012

0.995



78
0.926
0.933
2.46

1.23

0.89







79
0.933
0.939
2.46

1.23

0.89


0.019




80
0.939
0.945

1.39

0.69

0.50
0.019

0.993



81
0.945
0.951
2.46

1.23

0.89


0.012




82
0.951
0.957

1.39

0.69

0.50
0.012

0.993



83
0.957
0.963
2.46

1.23

0.89


0.012




84
0.963
0.968

1.39

0.69

0.50
0.012

0.993



85
0.968
0.975
2.46

1.23

0.89







86
0.975
0.981
2.46

1.23

0.89


0.018




87
0.981
0.987

1.39

0.69

0.50
0.018

0.995



88
0.987
0.993
2.46

1.23

0.89


0.012




89
0.993
0.998

1.39

0.69

0.50
0.011

0.997



90
0.998
1.005
2.46

1.23

0.89







91
1.005
1.010
2.46

1.23

0.89


0.018




92
1.010
1.016

1.39

0.69

0.50
0.018

0.993



93
1.016
1.022
2.46

1.23

0.89


0.011




94
1.022
1.027

1.39

0.69

0.50
0.011

0.993



95
1.027
1.034
2.46

1.23

0.89







96
1.034
1.039
2.46

1.23

0.89


0.017




97
1.039
1.045

1.39

0.69

0.50
0.017

0.998



98
1.045
1.051
2.46

1.23

0.89







99
1.051
1.056
2.46

1.23

0.89


0.017




100
1.056
1.062

1.39

0.69

0.50
0.017

0.993



101
1.062
1.068
2.46

1.23

0.89







102
1.068
1.073
2.46

1.23

0.89


0.017




103
1.073
1.078

1.39

0.69

0.50
0.017

0.994



104
1.078
1.085
2.46

1.23

0.89


0.023



Second Area
105
1.085
1.091
2.36

1.18

0.94







106
1.091
1.096
2.36

1.18

0.94







107
1.096
1.101

1.48

0.74

0.60
0.023

0.989



108
1.101
1.106
2.36

1.18

0.94


0.010




109
1.106
1.111

1.48

0.74

0.60
0.010

0.996



110
1.111
1.116
2.36

1.18

0.94


0.010




111
1.116
1.121

1.48

0.74

0.60
0.010

0.996



112
1.121
1.126
2.36

1.18

0.94


0.014




113
1.126
1.130

1.48

0.74

0.60
0.014

0.995



114
1.130
1.135

1.48

0.74

0.60






115
1.135
1.140
2.36

1.18

0.94


0.010




116
1.140
1.145

1.48

0.74

0.60
0.010

0.996



117
1.145
1.150
2.36

1.18

0.94


0.010




118
1.150
1.154

1.48

0.74

0.60
0.010

0.996



119
1.154
1.159
2.36

1.18

0.94


0.010




120
1.159
1.164

1.48

0.74

0.60
0.010

0.996




























TABLE 6C







Second Area
121
1.164
1.169
2.36

1.18

0.94


0.009




122
1.169
1.173

1.48

0.74

0.60
0.009

0.996



123
1.173
1.178
2.36

1.18

0.94


0.009




124
1.178
1.183

1.48

0.74

0.60
0.009

0.996



125
1.183
1.188
2.36

1.18

0.94


0.009




126
1.188
1.192

1.48

0.74

0.60
0.009

0.996



127
1.192
1.197
2.36

1.18

0.94


0.009




128
1.197
1.201

1.48

0.74

0.60
0.009

0.996



129
1.201
1.206
2.36

1.18

0.94


0.009




130
1.206
1.211

1.48

0.74

0.60
0.009

0.996



131
1.211
1.215
2.36

1.18

0.94


0.009




132
1.215
1.220

1.48

0.74

0.60
0.009

0.996



133
1.220
1.225
2.36

1.18

0.94


0.014




134
1.225
1.229
2.36

1.18

0.94







135
1.229
1.234

1.48

0.74

0.60
0.014

0.997



136
1.234
1.238
2.36

1.18

0.94


0.009




137
1.238
1.243

1.48

0.74

0.60
0.009

0.996



138
1.243
1.248
2.36

1.18

0.94


0.014




139
1.248
1.252
2.36

1.18

0.94







140
1.252
1.257

1.48

0.74

0.60
0.014

0.996



141
1.257
1.262
2.36

1.18

0.94


0.014




142
1.262
1.266
2.36

1.18

0.94







144
1.266
1.271

1.48

0.74

0.60
0.014

1.020



145
1.271
1.275
2.36

1.18

0.94


0.009




146
1.275
1.279

1.48

0.74

0.60
0.009

0.960



147
1.279
1.284
2.36

1.18

0.94







148
1.284
1.290
2.36

1.18

0.94






Third Area
149
1.290
1.353
4.00

2.00

0.88







150
1.353
1.393
4.00

2.00

0.88







151
1.393
1.418
4.00

2.00

0.88







152
1.418
1.437
4.00

2.00

0.88







153
1.437
1.452
4.00

2.00

0.88







154
1.452
1.465
4.00

2.00

0.88







155
1.465
1.476
4.00

2.00

0.88







156
1.476
1.486
4.00

2.00

0.88







157
1.486
1.495
4.00

2.00

0.88









FIG. 6A is a graph illustrating a wavefront aberration cased when the optical disc OD1 is used in the optical information recording/reproducing apparatus 100 according to the first example, FIG. 6B is a graph illustrating a wavefront aberration cased when the optical disc OD2 is used in the optical information recording/reproducing apparatus 100 according to the first example, and FIG. 6C is a graph illustrating a wavefront aberration cased when the optical disc OD3 is used in the optical information recording/reproducing apparatus 100 according to the first example. In each of FIGS. 6A, 6B and 6C, the vertical axis represents the amount wavefront aberration, and the horizontal axis represents the coordinate of the entrance pupil.
Second Example
Hereafter, a second example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the second example are shown in Tables 7 to 11 and 12A to 12C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the second example are shown in FIGS. 7A to 7C, respectively.












TABLE 7








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.765
1.990
2.053


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00





















TABLE 8







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.105
1.780


Objective Lens


1-2
1.050


1-3
1.039


2
−3.229
0.724
0.655
0.345


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 9






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
3.17140E−02
−2.91700E−01 
−2.33400E−02
 3.14670E−01


A6
1.04200E−02
4.89140E−01
 5.12560E−02
−6.04070E−01


A8
−1.26060E−03 
−2.22700E−01 
−2.77250E−02
 1.06890E+00


A10
−1.41370E−03 
2.26340E−02
 3.53320E−02
−1.23230E+00


A12
1.01710E−03
4.06430E−03
−2.96020E−02
 8.80450E−01


A14


 1.30850E−02
−3.78960E−01


A16


−2.25550E−03
 9.04170E−02


A18



−9.19750E−03


A20


A22


A24



















TABLE 10





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
5.57500E+01
7.51580E+01
3.02880E+01


P4
−1.37570E+01 
−2.86320E+02 
−4.99460E+01 


P6
7.03400E+00
4.43620E+02
3.04440E+01


P8
−5.26700E+00 
−2.41880E+02 
−6.61850E+00 


P10
6.53300E−01
4.29410E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 11







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.49340E+01
−2.15520E+01



P4
−5.73000E+00
−1.85150E+02



P6
−1.77800E+00
 2.85980E+02



P8
 9.42700E−01
−1.55790E+02



P10
−3.96600E−01
 2.77120E+01



P12
 0.00000E+00
 0.00000E+00




















TABLE 12A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.072












1
0.072
0.127

1.31

0.66

0.48






2
0.127
0.166
2.63

1.31

0.95


0.094




3
0.166
0.198

1.31

0.66

0.48
0.070

0.748



4
0.198
0.224
2.63

1.31

0.95


0.081




5
0.224
0.247

1.31

0.66

0.48
0.071

0.879



6
0.247
0.269

1.31

0.66

0.48






7
0.269
0.289
2.63

1.31

0.95


0.042




8
0.289
0.308

1.31

0.66

0.48
0.039

0.927



9
0.308
0.326
2.63

1.31

0.95


0.053




10
0.326
0.342

1.31

0.66

0.48
0.050

0.950



11
0.342
0.359

1.31

0.66

0.48






12
0.359
0.374
2.63

1.31

0.95


0.032




13
0.374
0.389

1.31

0.66

0.48
0.030

0.953



14
0.389
0.403
2.63

1.31

0.95


0.042




15
0.403
0.416

1.31

0.66

0.48
0.041

0.965



16
0.416
0.430

1.31

0.66

0.48






17
0.430
0.443
2.63

1.31

0.95


0.026




18
0.443
0.456

1.31

0.66

0.48
0.026

0.974



19
0.456
0.468
2.63

1.31

0.95


0.025




20
0.468
0.480

1.31

0.66

0.48
0.024

0.973



21
0.480
0.492
2.63

1.31

0.95


0.035




22
0.492
0.503

1.31

0.66

0.48
0.034

0.978



23
0.503
0.514

1.31

0.66

0.48






24
0.514
0.525
2.63

1.31

0.95


0.022




25
0.525
0.536

1.31

0.66

0.48
0.022

0.979



26
0.536
0.546
2.63

1.31

0.95


0.021




27
0.546
0.556

1.31

0.66

0.48
0.021

0.983



28
0.556
0.567
2.63

1.31

0.95


0.021




29
0.567
0.577

1.31

0.66

0.48
0.020

0.982



30
0.577
0.587
2.63

1.31

0.95


0.029




31
0.587
0.596

1.31

0.66

0.48
0.029

0.984



32
0.596
0.605

1.31

0.66

0.48






33
0.605
0.615
2.63

1.31

0.95


0.019




34
0.615
0.624

1.31

0.66

0.48
0.019

0.984



35
0.624
0.633
2.63

1.31

0.95


0.018




36
0.633
0.642

1.31

0.66

0.48
0.018

0.987



37
0.642
0.651
2.63

1.31

0.95


0.018




38
0.651
0.660

1.31

0.66

0.48
0.018

0.989



39
0.660
0.668
2.63

1.31

0.95


0.017




40
0.668
0.677

1.31

0.66

0.48
0.017

0.988



41
0.677
0.685
2.63

1.31

0.95


0.017




42
0.685
0.694

1.31

0.66

0.48
0.017

0.987



43
0.694
0.702
2.63

1.31

0.95


0.017




44
0.702
0.710

1.31

0.66

0.48
0.016

0.988



45
0.710
0.718
2.63

1.31

0.95


0.024




46
0.718
0.726

1.31

0.66

0.48
0.024

0.990



47
0.726
0.734

1.31

0.66

0.48






48
0.734
0.742
2.63

1.31

0.95


0.016




49
0.742
0.750

1.31

0.66

0.48
0.016

0.989



50
0.750
0.757
2.63

1.31

0.95


0.015




51
0.757
0.765

1.31

0.66

0.48
0.015

0.991



52
0.765
0.773
2.63

1.31

0.95


0.015




53
0.773
0.780

1.31

0.66

0.48
0.015

0.992



54
0.780
0.788
2.63

1.31

0.95


0.015




55
0.788
0.795

1.31

0.66

0.48
0.015

0.992



56
0.795
0.803
2.63

1.31

0.95


0.022




57
0.803
0.810
2.63

1.31

0.95







58
0.810
0.817

1.31

0.66

0.48
0.022

0.984



59
0.817
0.824
2.63

1.31

0.95


0.014




60
0.824
0.831

1.31

0.66

0.48
0.014

1.006




























TABLE 12B







First Area
61
0.831
0.838
2.63

1.31

0.95


0.014




62
0.838
0.845

1.31

0.66

0.48
0.014

0.992



63
0.845
0.852
2.63

1.31

0.95


0.014




64
0.852
0.859

1.31

0.66

0.48
0.014

0.992



65
0.859
0.866
2.63

1.31

0.95


0.014




66
0.866
0.873

1.31

0.66

0.48
0.014

0.993



67
0.873
0.879
2.63

1.31

0.95


0.014




68
0.879
0.886

1.31

0.66

0.48
0.013

0.995



69
0.886
0.893
2.63

1.31

0.95


0.013




70
0.893
0.900

1.31

0.66

0.48
0.013

0.994



71
0.900
0.906
2.63

1.31

0.95


0.020




72
0.906
0.913
2.63

1.31

0.95







73
0.913
0.919

1.31

0.66

0.48
0.020

0.995



74
0.919
0.926
2.63

1.31

0.95


0.013




75
0.926
0.932

1.31

0.66

0.48
0.013

0.993



76
0.932
0.939
2.63

1.31

0.95


0.013




77
0.939
0.945

1.31

0.66

0.48
0.013

0.993



78
0.945
0.952
2.63

1.31

0.95


0.019




79
0.952
0.958
2.63

1.31

0.95







80
0.958
0.964

1.31

0.66

0.48
0.019

0.995



81
0.964
0.971
2.63

1.31

0.95


0.012




82
0.971
0.977

1.31

0.66

0.48
0.012

0.996



83
0.977
0.983
2.63

1.31

0.95


0.012




84
0.983
0.989

1.31

0.66

0.48
0.012

0.994



85
0.989
0.995
2.63

1.31

0.95


0.019




86
0.995
1.002
2.63

1.31

0.95







87
1.002
1.008

1.31

0.66

0.48
0.019

0.996



88
1.008
1.014
2.63

1.31

0.95


0.018




89
1.014
1.020
2.63

1.31

0.95







90
1.020
1.026

1.31

0.66

0.48
0.018

0.996



91
1.026
1.032
2.63

1.31

0.95


0.012




92
1.032
1.038

1.31

0.66

0.48
0.012

0.995



93
1.038
1.044
2.63

1.31

0.95


0.018




94
1.044
1.050
2.63

1.31

0.95







95
1.050
1.056

1.31

0.66

0.48
0.018

0.997



96
1.056
1.062
2.63

1.31

0.95


0.018




97
1.062
1.068
2.63

1.31

0.95







98
1.068
1.073

1.31

0.66

0.48
0.018

0.996



99
1.073
1.079
2.63

1.31

0.95


0.025




100
1.079
1.085
2.63

1.31

0.95






Second Area
101
1.085
1.088
2.68

1.34

1.08







102
1.088
1.093

1.34

0.67

0.45
0.024

0.954



103
1.093
1.097

1.34

0.67

0.45






104
1.097
1.102
2.68

1.34

1.08


0.023




105
1.102
1.107

1.34

0.67

0.45
0.023

0.999



106
1.107
1.111

1.34

0.67

0.45






107
1.111
1.116

1.34

0.67

0.45






108
1.116
1.121

1.34

0.67

0.45






109
1.121
1.125
2.68

1.34

1.08


0.019




110
1.125
1.130

1.34

0.67

0.45
0.019

1.001



111
1.130
1.135

1.34

0.67

0.45






112
1.135
1.139

1.34

0.67

0.45






113
1.139
1.144
2.68

1.34

1.08


0.014




114
1.144
1.149

1.34

0.67

0.45
0.014

1.002



115
1.149
1.153

1.34

0.67

0.45






116
1.153
1.158
2.68

1.34

1.08


0.014




117
1.158
1.163

1.34

0.67

0.45
0.014

1.003



118
1.163
1.167

1.34

0.67

0.45






119
1.167
1.172
2.68

1.34

1.08


0.014




120
1.172
1.177

1.34

0.67

0.45
0.014

1.004




























TABLE 12C







Second Area
121
1.177
1.182

1.34

0.67

0.45






122
1.182
1.187
2.68

1.34

1.08


0.010




123
1.187
1.191

1.34

0.67

0.45
0.010

1.005



124
1.191
1.196
2.68

1.34

1.08


0.010




125
1.196
1.201

1.34

0.67

0.45
0.010

1.006



126
1.201
1.206
2.68

1.34

1.08


0.010




127
1.206
1.211

1.34

0.67

0.45
0.010

1.007



128
1.211
1.216
2.68

1.34

1.08


0.010




129
1.216
1.221

1.34

0.67

0.45
0.010

1.008



130
1.221
1.226
2.68

1.34

1.08


0.010




131
1.226
1.231

1.34

0.67

0.45
0.010

1.009



132
1.231
1.236
2.68

1.34

1.08


0.015




133
1.236
1.241
2.68

1.34

1.08







134
1.241
1.246

1.34

0.67

0.45
0.015

1.011



135
1.246
1.252
2.68

1.34

1.08


0.027




136
1.252
1.257
2.68

1.34

1.08







137
1.257
1.262
2.68

1.34

1.08







138
1.262
1.268
2.68

1.34

1.08







139
1.268
1.273

1.34

0.67

0.45
0.027

1.015



140
1.273
1.279
2.68

1.34

1.08







141
1.279
1.285
2.68

1.34

1.08







142
1.285
1.290
2.68

1.34

1.08






Third Area
144
1.290
1.300
2.00

1.00

0.89







145
1.300
1.353
2.00

1.00

0.89







146
1.353
1.388
2.00

1.00

0.89







147
1.388
1.388
2.00

1.00

0.89







148
1.388
1.413
2.00

1.00

0.89







149
1.413
1.433
2.00

1.00

0.89







150
1.433
1.450
2.00

1.00

0.89







151
1.450
1.465
2.00

1.00

0.89







152
1.465
1.478
2.00

1.00

0.89







153
1.478
1.489
2.00

1.00

0.89







154
1.489
1.500
2.00

1.00

0.89









Third Example
Hereafter, a third example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the third example are shown in Tables 13 to 17 and 18A to 18C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the third example are shown in FIGS. 8A to 8C, respectively.












TABLE 13








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.765
1.990
2.065


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00





















TABLE 14







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.074
1.950


Objective Lens


1-2
1.155


1-3
0.962


2
−2.706
0.641
0.589
0.300


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 15






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
2.70700E−02
8.62100E−02
−8.34760E−02
 4.42160E−01


A6
2.01320E−02
9.10300E−05
 7.01540E−02
−7.04410E−01


A8
−3.61030E−03 
−1.42300E−02 
−1.12120E−02
 1.01100E+00


A10
1.52870E−03
2.71430E−03
 8.35390E−03
−1.10310E+00


A12
−3.25800E−04 
9.73660E−04
−7.80650E−03
 8.32790E−01


A14


 3.79750E−03
−3.90120E−01


A16


−7.52710E−04
 9.89130E−02


A18



−9.59370E−03


A20


A22


A24



















TABLE 16





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
7.42110E+01
4.74760E+01
6.00180E+01


P4
−1.80070E+01 
3.31230E+01
−9.50580E+01 


P6
1.05850E+01
−8.79100E+00 
5.20440E+01


P8
−3.89500E+00 
−1.53740E+01 
−1.00470E+01 


P10
6.00000E−02
5.33400E+00
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 17







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−2.91500E+01
−4.75780E+01



P4
−9.11300E+00
 2.73130E+01



P6
 6.26900E+00
−1.00070E+01



P8
−4.21500E+00
−9.93300E+00



P10
 5.35900E−01
 3.76400E+00



P12
 0.00000E+00
 0.00000E+00





















TABLE 18A








Phase






Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.067












1
0.067
0.121

1.59

0.79

0.57






2
0.121
0.159
2.30

1.15

0.83


0.140




3
0.159
0.184

1.59

0.79

0.57
0.109

0.783



4
0.184
0.207

1.59

0.79

0.57






5
0.207
0.231

1.59

0.79

0.57






6
0.231
0.252
2.30

1.15

0.83


0.063




7
0.252
0.269

1.59

0.79

0.57
0.057

0.916



8
0.269
0.288

1.59

0.79

0.57






9
0.288
0.306
2.30

1.15

0.83


0.050




10
0.306
0.320

1.59

0.79

0.57
0.048

0.946



11
0.320
0.336

1.59

0.79

0.57






12
0.336
0.351
2.30

1.15

0.83


0.056




13
0.351
0.363

1.59

0.79

0.57
0.053

0.960



14
0.363
0.375

1.59

0.79

0.57






15
0.375
0.389

1.59

0.79

0.57






16
0.389
0.402
2.30

1.15

0.83


0.038




17
0.402
0.413

1.59

0.79

0.57
0.037

0.969



18
0.413
0.426

1.59

0.79

0.57






19
0.426
0.438
2.30

1.15

0.83


0.035




20
0.438
0.448

1.59

0.79

0.57
0.034

0.972



21
0.448
0.460

1.59

0.79

0.57






22
0.460
0.471
2.30

1.15

0.83


0.032




23
0.471
0.481

1.59

0.79

0.57
0.032

0.977



24
0.481
0.491

1.59

0.79

0.57






25
0.491
0.502
2.30

1.15

0.83


0.030




26
0.502
0.511

1.59

0.79

0.57
0.030

0.980



27
0.511
0.521

1.59

0.79

0.57






28
0.521
0.531
2.30

1.15

0.83


0.029




29
0.531
0.540

1.59

0.79

0.57
0.028

0.981



30
0.540
0.549

1.59

0.79

0.57






31
0.549
0.559
2.30

1.15

0.83


0.027




32
0.559
0.567

1.59

0.79

0.57
0.027

0.983



33
0.567
0.576

1.59

0.79

0.57






34
0.576
0.585
2.30

1.15

0.83


0.026




35
0.585
0.593

1.59

0.79

0.57
0.026

0.986



36
0.593
0.602

1.59

0.79

0.57






37
0.602
0.611
2.30

1.15

0.83


0.025




38
0.611
0.618

1.59

0.79

0.57
0.025

0.986



39
0.618
0.627

1.59

0.79

0.57






40
0.627
0.635
2.30

1.15

0.83


0.024




41
0.635
0.642

1.59

0.79

0.57
0.024

0.986



42
0.642
0.650

1.59

0.79

0.57






43
0.650
0.659
2.30

1.15

0.83


0.016




44
0.659
0.667

1.59

0.79

0.57
0.016

0.989



45
0.667
0.675
2.30

1.15

0.83


0.023




46
0.675
0.681

1.59

0.79

0.57
0.022

0.988



47
0.681
0.689

1.59

0.79

0.57






48
0.689
0.697
2.30

1.15

0.83


0.022




49
0.697
0.703

1.59

0.79

0.57
0.022

0.990



50
0.703
0.711

1.59

0.79

0.57






51
0.711
0.718
2.30

1.15

0.83


0.021




52
0.718
0.724

1.59

0.79

0.57
0.021

0.989



53
0.724
0.732

1.59

0.79

0.57






54
0.732
0.739
2.30

1.15

0.83


0.022




55
0.739
0.746

1.59

0.79

0.57
0.014

0.664



56
0.746
0.753
2.30

1.15

0.83


0.020




57
0.753
0.759

1.59

0.79

0.57
0.020

0.990



58
0.759
0.766

1.59

0.79

0.57






59
0.766
0.773
2.30

1.15

0.83


0.020




60
0.773
0.779

1.59

0.79

0.57
0.020

0.992




























TABLE 18B







First Area
61
0.779
0.786

1.59

0.79

0.57






62
0.786
0.793
2.30

1.15

0.83


0.014




63
0.793
0.799

1.59

0.79

0.57
0.013

0.990



64
0.799
0.806
2.30

1.15

0.83


0.019




65
0.806
0.812

1.59

0.79

0.57
0.019

0.992



66
0.812
0.818

1.59

0.79

0.57






67
0.818
0.825
2.30

1.15

0.83


0.018




68
0.825
0.830

1.59

0.79

0.57
0.018

0.992



69
0.830
0.836

1.59

0.79

0.57






70
0.836
0.843
2.30

1.15

0.83


0.013




71
0.843
0.849

1.59

0.79

0.57
0.013

0.992



72
0.849
0.855
2.30

1.15

0.83


0.018




73
0.855
0.861

1.59

0.79

0.57
0.018

0.993



74
0.861
0.867

1.59

0.79

0.57






75
0.867
0.873
2.30

1.15

0.83


0.012




76
0.873
0.879

1.59

0.79

0.57
0.012

0.992



77
0.879
0.885
2.30

1.15

0.83


0.017




78
0.885
0.890

1.59

0.79

0.57
0.017

0.992



79
0.890
0.896

1.59

0.79

0.57






80
0.896
0.902
2.30

1.15

0.83


0.012




81
0.902
0.908

1.59

0.79

0.57
0.012

0.993



82
0.908
0.914
2.30

1.15

0.83


0.017




83
0.914
0.918

1.59

0.79

0.57
0.016

0.993



84
0.918
0.924

1.59

0.79

0.57






85
0.924
0.930
2.30

1.15

0.83


0.011




86
0.930
0.936

1.59

0.79

0.57
0.011

0.993



87
0.936
0.941
2.30

1.15

0.83


0.011




88
0.941
0.947

1.59

0.79

0.57
0.011

0.994



89
0.947
0.952
2.30

1.15

0.83


0.016




90
0.952
0.957

1.59

0.79

0.57
0.016

0.993



91
0.957
0.963

1.59

0.79

0.57






92
0.963
0.968
2.30

1.15

0.83


0.011




93
0.968
0.973

1.59

0.79

0.57
0.011

0.993



94
0.973
0.979
2.30

1.15

0.83


0.011




95
0.979
0.984

1.59

0.79

0.57
0.011

0.994



96
0.984
0.989
2.30

1.15

0.83


0.015




97
0.989
0.994

1.59

0.79

0.57
0.015

0.994



98
0.994
0.999

1.59

0.79

0.57






99
0.999
1.004
2.30

1.15

0.83


0.010




100
1.004
1.010

1.59

0.79

0.57
0.010

0.994



101
1.010
1.015
2.30

1.15

0.83


0.010




102
1.015
1.020

1.59

0.79

0.57
0.010

0.993



103
1.020
1.025
2.30

1.15

0.83


0.010




104
1.025
1.030

1.59

0.79

0.57
0.010

0.995



105
1.030
1.035
2.30

1.15

0.83


0.014




106
1.035
1.039

1.59

0.79

0.57
0.014

0.994



107
1.039
1.044

1.59

0.79

0.57






108
1.044
1.049
2.30

1.15

0.83


0.010




109
1.049
1.054

1.59

0.79

0.57
0.010

0.994



110
1.054
1.059
2.30

1.15

0.83


0.010




111
1.059
1.064

1.59

0.79

0.57
0.010

0.995



112
1.064
1.069
2.30

1.15

0.83


0.010




113
1.069
1.074

1.59

0.79

0.57
0.010

0.994



114
1.074
1.078
2.30

1.15

0.83


0.010




115
1.078
1.083

1.59

0.79

0.57
0.010





116
1.083
1.090
2.30

1.15

0.83






Second Area
117
1.090
1.097
2.25

1.12

0.90


0.023




118
1.097
1.102
2.25

1.12

0.90







119
1.102
1.107

1.64

0.82

0.66
0.023

0.997



120
1.107
1.112
2.25

1.12

0.90


0.015




























TABLE 18C







Second Area
121
1.112
1.117
2.25

1.12

0.90







122
1.117
1.121

1.64

0.82

0.66
0.015

0.995



123
1.121
1.127
2.25

1.12

0.90


0.015




124
1.127
1.131
2.25

1.12

0.90







125
1.131
1.136

1.64

0.82

0.66
0.015

0.995



126
1.136
1.141
2.25

1.12

0.90


0.014




127
1.141
1.146
2.25

1.12

0.90







128
1.146
1.150

1.64

0.82

0.66
0.014

0.995



129
1.150
1.156
2.25

1.12

0.90


0.014




130
1.156
1.160
2.25

1.12

0.90







131
1.160
1.165

1.64

0.82

0.66
0.014

0.996



132
1.165
1.170
2.25

1.12

0.90


0.014




133
1.170
1.174
2.25

1.12

0.90







134
1.174
1.179

1.64

0.82

0.66
0.014

0.996



135
1.179
1.184
2.25

1.12

0.90


0.019




136
1.184
1.189
2.25

1.12

0.90







137
1.189
1.193
2.25

1.12

0.90







138
1.193
1.198

1.64

0.82

0.66
0.019

0.996



139
1.198
1.203
2.25

1.12

0.90


0.024




140
1.203
1.208
2.25

1.12

0.90







141
1.208
1.213
2.25

1.12

0.90







142
1.213
1.217
2.25

1.12

0.90







144
1.217
1.221

1.64

0.82

0.66
0.024

0.996



145
1.221
1.226
2.25

1.12

0.90


0.033




146
1.226
1.231
2.25

1.12

0.90







147
1.231
1.236
2.25

1.12

0.90







148
1.236
1.241
2.25

1.12

0.90







149
1.241
1.246
2.25

1.12

0.90







150
1.246
1.250
2.25

1.12

0.90







151
1.250
1.254

1.64

0.82

0.66
0.033

0.996



152
1.254
1.259
2.25

1.12

0.90







153
1.259
1.263
2.25

1.12

0.90







154
1.263
1.268
2.25

1.12

0.90







155
1.268
1.274
2.25

1.12

0.90







156
1.274
1.279
2.25

1.12

0.90







157
1.279
1.284
2.25

1.12

0.90







158
1.284
1.290
2.25

1.12

0.90






Third Area
159
1.290
1.327
4.00

2.00

0.86







160
1.327
1.361
4.00

2.00

0.86







161
1.361
1.389
4.00

2.00

0.86







162
1.389
1.412
4.00

2.00

0.86







163
1.412
1.431
4.00

2.00

0.86







164
1.431
1.448
4.00

2.00

0.86







165
1.448
1.462
4.00

2.00

0.86







166
1.462
1.475
4.00

2.00

0.86







167
1.475
1.486
4.00

2.00

0.86







168
1.486
1.500
4.00

2.00

0.86









Fourth Example
Hereafter, a fourth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the fourth example are shown in Tables 19 to 23 and 24A to 24C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the fourth example are shown in FIGS. 9A to 9C, respectively.












TABLE 19








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.769
1.990
2.041


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00





















TABLE 20







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.154
2.110


Objective Lens


1-2
1.149


1-3
0.936


2
−2.399
0.554
0.517
0.201


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 21






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
2.26600E−02
−8.26030E−02 
−1.10670E−01
5.54800E−01


A6
1.36540E−02
1.70530E−01
 6.51190E−02
−8.60700E−01 


A8
−1.29800E−03 
−7.22300E−02 
−6.97660E−03
1.10520E+00


A10
9.27250E−04
9.61100E−03
 5.04510E−03
−1.10220E+00 


A12
−6.44100E−04 
1.44600E−04
−4.22510E−03
8.32800E−01


A14


 2.01620E−03
−3.85130E−01 


A16


−4.02380E−04
7.18230E−02


A18



6.65290E−03


A20


A22


A24



















TABLE 22





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
 5.10310E+01
5.25750E+01
7.00300E+01


P4
−1.74740E+01
−1.03600E+02 
−1.14880E+02 


P6
 5.47100E+00
1.42690E+02
5.15700E+01


P8
−8.91800E−01
−7.14060E+01 
−7.84700E+00 


P10
−7.62500E−01
1.14300E+01
0.00000E+00


P12
 0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 23







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−5.05620E+01
−4.94980E+01



P4
−9.03900E+00
−6.87640E+01



P6
 4.93600E+00
 1.03820E+02



P8
−2.97800E+00
−5.67320E+01



P10
−3.44400E−02
 9.91000E+00



P12
 0.00000E+00
 0.00000E+00




















TABLE 24A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.064












1
0.064
0.113

1.39

0.69

0.50






2
0.113
0.165
2.19

1.10

0.79


0.130




3
0.165
0.193
2.19

1.10

0.79







4
0.193
0.217

1.39

0.69

0.50
0.103

0.799



5
0.217
0.237
2.19

1.10

0.79


0.044




6
0.237
0.258

1.39

0.69

0.50
0.041

0.937



7
0.258
0.276
2.19

1.10

0.79


0.039




8
0.276
0.293

1.39

0.69

0.50
0.035

0.894



9
0.293
0.310
2.19

1.10

0.79


0.034




10
0.310
0.324

1.39

0.69

0.50
0.032

0.935



11
0.324
0.339
2.19

1.10

0.79


0.030




12
0.339
0.353

1.39

0.69

0.50
0.029

0.972



13
0.353
0.367
2.19

1.10

0.79


0.027




14
0.367
0.380

1.39

0.69

0.50
0.027

0.973



15
0.380
0.392
2.19

1.10

0.79


0.026




16
0.392
0.405

1.39

0.69

0.50
0.025

0.960



17
0.405
0.417
2.19

1.10

0.79


0.024




18
0.417
0.428

1.39

0.69

0.50
0.023

0.960



19
0.428
0.439
2.19

1.10

0.79


0.023




20
0.439
0.450

1.39

0.69

0.50
0.022

0.978



21
0.450
0.466
2.19

1.10

0.79


0.037




22
0.466
0.477
2.19

1.10

0.79







23
0.477
0.487

1.39

0.69

0.50
0.036

0.976



24
0.487
0.497
2.19

1.10

0.79


0.020




25
0.497
0.506

1.39

0.69

0.50
0.020

0.989



26
0.506
0.516
2.19

1.10

0.79


0.019




27
0.516
0.525

1.39

0.69

0.50
0.019

0.991



28
0.525
0.534
2.19

1.10

0.79


0.019




29
0.534
0.543

1.39

0.69

0.50
0.018

0.978



30
0.543
0.556
2.19

1.10

0.79


0.031




31
0.556
0.565
2.19

1.10

0.79







32
0.565
0.574

1.39

0.69

0.50
0.031

0.989



33
0.574
0.582
2.19

1.10

0.79


0.017




34
0.582
0.590

1.39

0.69

0.50
0.017

0.974



35
0.590
0.598
2.19

1.10

0.79


0.016




36
0.598
0.606

1.39

0.69

0.50
0.016

0.984



37
0.606
0.618
2.19

1.10

0.79


0.028




38
0.618
0.626
2.19

1.10

0.79







39
0.626
0.634

1.39

0.69

0.50
0.027

0.987



40
0.634
0.641
2.19

1.10

0.79


0.015




41
0.641
0.649

1.39

0.69

0.50
0.015

1.001



42
0.649
0.660
2.19

1.10

0.79


0.026




43
0.660
0.667
2.19

1.10

0.79







44
0.667
0.674

1.39

0.69

0.50
0.025

0.979



45
0.674
0.681
2.19

1.10

0.79


0.014




46
0.681
0.688

1.39

0.69

0.50
0.014

0.994



47
0.688
0.699
2.19

1.10

0.79


0.024




48
0.699
0.705
2.19

1.10

0.79







49
0.705
0.712

1.39

0.69

0.50
0.024

0.993



50
0.712
0.719
2.19

1.10

0.79


0.014




51
0.719
0.725

1.39

0.69

0.50
0.013

0.974



52
0.725
0.735
2.19

1.10

0.79


0.023




53
0.735
0.742
2.19

1.10

0.79







54
0.742
0.748

1.39

0.69

0.50
0.023

0.997



55
0.748
0.758
2.19

1.10

0.79


0.022




56
0.758
0.764
2.19

1.10

0.79







57
0.764
0.770

1.39

0.69

0.50
0.022

0.987



58
0.770
0.776
2.19

1.10

0.79


0.012




59
0.776
0.782

1.39

0.69

0.50
0.012

1.001



60
0.782
0.791
2.19

1.10

0.79


0.021




























TABLE 24B







First Area
61
0.791
0.797
2.19

1.10

0.79







62
0.797
0.803

1.39

0.69

0.50
0.021

0.988



63
0.803
0.812
2.19

1.10

0.79


0.020




64
0.812
0.818
2.19

1.10

0.79







65
0.818
0.823

1.39

0.69

0.50
0.020

0.993



66
0.823
0.832
2.19

1.10

0.79


0.020




67
0.832
0.838
2.19

1.10

0.79







68
0.838
0.843

1.39

0.69

0.50
0.020

0.971



69
0.843
0.849
2.19

1.10

0.79


0.011




70
0.849
0.854

1.39

0.69

0.50
0.011

1.032



71
0.854
0.862
2.19

1.10

0.79


0.019




72
0.862
0.868
2.19

1.10

0.79







73
0.868
0.873

1.39

0.69

0.50
0.019

0.996



74
0.873
0.881
2.19

1.10

0.79


0.019




75
0.881
0.886
2.19

1.10

0.79







76
0.886
0.891

1.39

0.69

0.50
0.018

0.991



77
0.891
0.899
2.19

1.10

0.79


0.018




78
0.899
0.904
2.19

1.10

0.79







79
0.904
0.909

1.39

0.69

0.50
0.018

0.988



80
0.909
0.917
2.19

1.10

0.79


0.018




81
0.917
0.922
2.19

1.10

0.79







82
0.922
0.927

1.39

0.69

0.50
0.018

0.992



83
0.927
0.934
2.19

1.10

0.79


0.025




84
0.934
0.942
2.19

1.10

0.79







85
0.942
0.947
2.19

1.10

0.79







86
0.947
0.951

1.39

0.69

0.50
0.024

0.993



87
0.951
0.958
2.19

1.10

0.79


0.017




88
0.958
0.963
2.19

1.10

0.79







89
0.963
0.968

1.39

0.69

0.50
0.017

0.998



90
0.968
0.975
2.19

1.10

0.79


0.016




91
0.975
0.979
2.19

1.10

0.79







92
0.979
0.984

1.39

0.69

0.50
0.016

0.991



93
0.984
0.991
2.19

1.10

0.79


0.023




94
0.991
0.998
2.19

1.10

0.79







95
0.998
1.002
2.19

1.10

0.79







96
1.002
1.007

1.39

0.69

0.50
0.023

0.997



97
1.007
1.013
2.19

1.10

0.79


0.022




98
1.013
1.020
2.19

1.10

0.79







99
1.020
1.024
2.19

1.10

0.79







100
1.024
1.028

1.39

0.69

0.50
0.022

0.993



101
1.028
1.035
2.19

1.10

0.79


0.021




102
1.035
1.041
2.19

1.10

0.79







103
1.041
1.046
2.19

1.10

0.79







104
1.046
1.050

1.39

0.69

0.50
0.021

0.993



105
1.050
1.056
2.19

1.10

0.79


0.021




106
1.056
1.062
2.19

1.10

0.79







107
1.062
1.066
2.19

1.10

0.79







108
1.066
1.070

1.39

0.69

0.50
0.021

0.995



109
1.070
1.078
2.19

1.10

0.79


0.011




110
1.078
1.085

1.39

0.69

0.50
0.012

1.041


Second Area
111
1.085
1.090
2.19

1.10

0.87







112
1.090
1.095
2.19

1.10

0.87


0.017




113
1.095
1.099

1.39

0.69

0.55
0.017

0.988



114
1.099
1.103
2.19

1.10

0.87


0.009




115
1.103
1.107

1.39

0.69

0.55
0.008

0.993



116
1.107
1.112
2.19

1.10

0.87


0.008




117
1.112
1.116

1.39

0.69

0.55
0.008

0.993



118
1.116
1.120
2.19

1.10

0.87


0.008




119
1.120
1.124

1.39

0.69

0.55
0.008

0.993



120
1.124
1.130
2.19

1.10

0.87


0.014




























TABLE 24C







Second Area
121
1.130
1.134
2.19

1.10

0.87







122
1.134
1.138

1.39

0.69

0.55
0.014

0.993



123
1.138
1.142
2.19

1.10

0.87


0.008




124
1.142
1.146

1.39

0.69

0.55
0.008

0.993



125
1.146
1.152
2.19

1.10

0.87


0.014




126
1.152
1.156
2.19

1.10

0.87







127
1.156
1.160

1.39

0.69

0.55
0.014

0.999



128
1.160
1.164
2.19

1.10

0.87


0.008




129
1.164
1.168

1.39

0.69

0.55
0.008

0.982



130
1.168
1.173
2.19

1.10

0.87


0.013




131
1.173
1.177
2.19

1.10

0.87







132
1.177
1.181

1.39

0.69

0.55
0.013

0.993



133
1.181
1.184
2.19

1.10

0.87


0.007




134
1.184
1.188

1.39

0.69

0.55
0.007

0.992



135
1.188
1.194
2.19

1.10

0.87


0.013




136
1.194
1.197
2.19

1.10

0.87







137
1.197
1.201

1.39

0.69

0.55
0.013

0.993



138
1.201
1.206
2.19

1.10

0.87


0.012




139
1.206
1.210
2.19

1.10

0.87







140
1.210
1.213

1.39

0.69

0.55
0.012

0.993



141
1.213
1.218
2.19

1.10

0.87


0.012




142
1.218
1.222
2.19

1.10

0.87







143
1.222
1.225

1.39

0.69

0.55
0.012

0.993



144
1.225
1.230
2.19

1.10

0.87


0.017




145
1.230
1.235
2.19

1.10

0.87







146
1.235
1.239
2.19

1.10

0.87







147
1.239
1.242

1.39

0.69

0.55
0.017

0.993



148
1.242
1.247
2.19

1.10

0.87


0.011




149
1.247
1.250
2.19

1.10

0.87







150
1.250
1.253

1.39

0.69

0.55
0.011

0.993



151
1.253
1.258
2.19

1.10

0.87


0.019




152
1.258
1.263
2.19

1.10

0.87







153
1.263
1.268
2.19

1.10

0.87







154
1.268
1.270
2.19

1.10

0.87







155
1.270
1.273

1.39

0.69

0.55
0.020

1.017



156
1.273
1.278
2.19

1.10

0.87







157
1.278
1.283
2.19

1.10

0.87







158
1.283
1.290
2.19

1.10

0.87






Third Area
159
1.290
1.295
4.00

2.00

0.83







160
1.295
1.309
4.00

2.00

0.83







161
1.309
1.323
4.00

2.00

0.83







162
1.323
1.338
4.00

2.00

0.83







163
1.338
1.352
4.00

2.00

0.83







164
1.352
1.368
4.00

2.00

0.83







165
1.368
1.383
4.00

2.00

0.83







166
1.383
1.399
4.00

2.00

0.83







167
1.399
1.415
4.00

2.00

0.83







168
1.415
1.431
4.00

2.00

0.83







169
1.431
1.448
4.00

2.00

0.83







170
1.448
1.464
4.00

2.00

0.83







171
1.464
1.481
4.00

2.00

0.83







172
1.481
1.500
4.00

2.00

0.83









Fifth Example
Hereafter, a fifth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the fifth example are shown in Tables 25 to 29 and 30A and 30B. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the fifth example are shown in FIGS. 10A to 10C, respectively.












TABLE 25








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.764
2.044
2.119


NA

0.85
0.62
0.50


Magnification

0.00
0.00
0.00





















TABLE 26







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.186
1.680


Objective Lens


1-2
1.201


1-3
1.100


2
−9.001
0.752
0.689
0.379


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.65098
1.59978
1.59073

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 27






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
3.39000E−02
−9.62700E−02 
1.79490E−02
 2.16910E−01


A6
9.47600E−03
2.28350E−01
2.60340E−03
−4.68760E−01


A8
−2.83860E−03 
−1.10000E−01 
−2.84670E−03 
 8.59730E−01


A10
9.40900E−04
1.31960E−02
9.73240E−03
−1.06950E+00


A12
−4.56600E−05 
2.03100E−03
−8.23430E−03 
 8.33790E−01


A14


4.12920E−03
−3.93780E−01


A16


−8.03760E−04 
 1.03440E−01


A18



−1.16320E−02


A20


A22


A24



















TABLE 28





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
3.89120E+01
3.41270E+01
3.57850E+01


P4
−1.14340E+01 
−1.30400E+02 
−2.33500E+01 


P6
5.76600E+00
2.22700E+02
−3.37100E+00 


P8
−4.78900E+00 
−1.29100E+02 
2.53300E+00


P10
5.43500E−01
2.43190E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 29







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−2.03220E+01
−2.40000E+01



P4
−2.82600E+00
−9.22200E+01



P6
−1.42400E+00
 1.63320E+02



P8
−1.27200E−01
−9.56250E+01



P10
−1.30700E−01
 1.83210E+01



P12
 0.00000E+00
 0.00000E+00




















TABLE 30A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.085












1
0.085
0.158

1.32

0.66

0.41






2
0.158
0.207
2.47

1.24

0.77


0.157




3
0.207
0.242

1.32

0.66

0.41
0.118

0.754



4
0.242
0.277

1.32

0.66

0.41






5
0.277
0.308
2.47

1.24

0.77


0.090




6
0.308
0.331

1.32

0.66

0.41
0.081

0.910



7
0.331
0.358

1.32

0.66

0.41






8
0.358
0.383
2.47

1.24

0.77


0.075




9
0.383
0.406

1.32

0.66

0.41
0.048

0.644



10
0.406
0.428
2.47

1.24

0.77


0.063




11
0.428
0.446

1.32

0.66

0.41
0.060

0.951



12
0.446
0.466

1.32

0.66

0.41






13
0.466
0.485
2.47

1.24

0.77


0.040




14
0.485
0.504

1.32

0.66

0.41
0.038

0.963



15
0.504
0.522
2.47

1.24

0.77


0.051




16
0.522
0.536

1.32

0.66

0.41
0.049

0.967



17
0.536
0.553

1.32

0.66

0.41






18
0.553
0.570
2.47

1.24

0.77


0.034




19
0.570
0.586

1.32

0.66

0.41
0.033

0.973



20
0.586
0.602
2.47

1.24

0.77


0.044




21
0.602
0.614

1.32

0.66

0.41
0.043

0.975



22
0.614
0.629

1.32

0.66

0.41






23
0.629
0.644
2.47

1.24

0.77


0.030




24
0.644
0.658

1.32

0.66

0.41
0.029

0.979



25
0.658
0.673
2.47

1.24

0.77


0.028




26
0.673
0.686

1.32

0.66

0.41
0.028

0.981



27
0.686
0.700
2.47

1.24

0.77


0.038




28
0.700
0.711

1.32

0.66

0.41
0.038

0.982



29
0.711
0.724

1.32

0.66

0.41






30
0.724
0.737
2.47

1.24

0.77


0.026




31
0.737
0.750

1.32

0.66

0.41
0.026

0.984



32
0.750
0.762
2.47

1.24

0.77


0.025




33
0.762
0.775

1.32

0.66

0.41
0.025

0.985



34
0.775
0.787
2.47

1.24

0.77


0.025




35
0.787
0.799

1.32

0.66

0.41
0.024

0.986



36
0.799
0.811
2.47

1.24

0.77


0.024




37
0.811
0.822

1.32

0.66

0.41
0.024

0.987



38
0.822
0.834
2.47

1.24

0.77


0.023




39
0.834
0.845

1.32

0.66

0.41
0.023

0.988



40
0.845
0.857
2.47

1.24

0.77


0.023




41
0.857
0.868

1.32

0.66

0.41
0.022

0.988



42
0.868
0.879
2.47

1.24

0.77


0.022




43
0.879
0.890

1.32

0.66

0.41
0.022

0.989



44
0.890
0.902
2.47

1.24

0.77


0.034




45
0.902
0.913
2.47

1.24

0.77







46
0.913
0.924

1.32

0.66

0.41
0.034

0.990



47
0.924
0.934
2.47

1.24

0.77


0.021




48
0.934
0.944

1.32

0.66

0.41
0.021

0.991



49
0.944
0.955
2.47

1.24

0.77


0.021




50
0.955
0.965

1.32

0.66

0.41
0.020

0.991



51
0.965
0.977
2.47

1.24

0.77


0.032




52
0.977
0.987
2.47

1.24

0.77







53
0.987
0.997

1.32

0.66

0.41
0.032

0.991



54
0.997
1.008
2.47

1.24

0.77


0.031




55
1.008
1.018
2.47

1.24

0.77







56
1.018
1.028

1.32

0.66

0.41
0.031

0.992



57
1.028
1.039
2.47

1.24

0.77


0.030




58
1.039
1.048
2.47

1.24

0.77







59
1.048
1.058

1.32

0.66

0.41
0.030

0.993



60
1.058
1.069
2.47

1.24

0.77


0.050




























TABLE 30B







First Area
61
1.069
1.080
2.47

1.24

0.77







62
1.080
1.085
2.47

1.24

0.77







63
1.085
1.092
2.53

1.27

0.87






Second Area
64
1.092
1.099

1.44

0.72

0.51
0.051

1.019



65
1.099
1.109

1.44

0.72

0.51






66
1.109
1.119
2.53

1.27

0.87


0.034




67
1.119
1.126

1.44

0.72

0.51
0.034

0.989



68
1.126
1.133

1.44

0.72

0.51






69
1.133
1.143

1.44

0.72

0.51






70
1.143
1.153
2.53

1.27

0.87


0.026




71
1.153
1.159

1.44

0.72

0.51
0.026

0.988



72
1.159
1.169

1.44

0.72

0.51






73
1.169
1.179
2.53

1.27

0.87


0.026




74
1.179
1.185

1.44

0.72

0.51
0.025

0.987



75
1.185
1.194

1.44

0.72

0.51






76
1.194
1.204
2.53

1.27

0.87


0.019




77
1.204
1.213

1.44

0.72

0.51
0.018

0.987



78
1.213
1.222
2.53

1.27

0.87


0.018




79
1.222
1.231

1.44

0.72

0.51
0.018

0.986



80
1.231
1.242
2.53

1.27

0.87


0.029




81
1.242
1.251
2.53

1.27

0.87







82
1.251
1.259

1.44

0.72

0.51
0.029

0.986



83
1.259
1.270
2.53

1.27

0.87







84
1.270
1.281
2.53

1.27

0.87







85
1.281
1.290
2.53

1.27

0.87






Third Area
86
1.290
1.311
2.00

1.00

0.75







87
1.311
1.328
2.00

1.00

0.75







88
1.328
1.345
2.00

1.00

0.75







89
1.345
1.362
2.00

1.00

0.75







90
1.362
1.380
2.00

1.00

0.75







91
1.380
1.399
2.00

1.00

0.75







92
1.399
1.419
2.00

1.00

0.75







93
1.419
1.442
2.00

1.00

0.75







94
1.442
1.500
2.00

1.00

0.75









Sixth Example
Hereafter, a sixth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the sixth example are shown in Tables 31 to 35 and 36A to 36C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the sixth example are shown in FIGS. 11A to 11C, respectively.












TABLE 31








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.764
1.987
2.049


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00





















TABLE 32







Surface







No.
R
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.065
1.880


Objective Lens


1-2
1.070


1-3
0.930


2
−2.321
0.682
0.636
0.332


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.52469
1.50635
1.50313

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 33






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
1.480







A4
2.78600E−02
−1.06900E−01 
−5.44570E−02
3.75670E−01


A6
1.30660E−02
2.29200E−01
 5.02410E−02
−3.90040E−01 


A8
1.72500E−03
−1.01400E−01 
−8.23860E−03
3.09680E−01


A10
6.15300E−04
1.40000E−02
 8.31250E−03
−1.55690E−01 


A12
−6.79800E−04 
4.48150E−04
−4.12600E−03
3.92700E−02


A14


−1.10690E−04
1.81960E−03


A16


 9.60710E−04
−1.75900E−03 


A18


−2.79660E−04
−9.38060E−04 


A20



3.92970E−04


A22


A24



















TABLE 34





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
6.34550E+01
6.17720E+01
5.65130E+01


P4
−1.46570E+01 
−1.18800E+02 
−7.12700E+01 


P6
2.11500E+00
1.81570E+02
3.29000E+01


P8
1.56700E+00
−9.60000E+01 
−5.71400E+00 


P10
−1.36100E+00 
1.63070E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 35







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.87210E+01
−3.98800E+01



P4
−9.27300E+00
−7.91270E+01



P6
 5.25200E+00
 1.29200E+02



P8
−2.65800E+00
−7.28570E+01



P10
−1.28300E−01
 1.32200E+01



P12
 0.00000E+00
 0.00000E+00




















TABLE 36A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.070












1
0.070
0.121

1.17

0.59

0.45






2
0.121
0.157
2.73

1.37

1.06


0.087




3
0.157
0.186

1.17

0.59

0.45
0.065

0.743



4
0.186
0.211
2.73

1.37

1.06


0.075




5
0.211
0.232

1.17

0.59

0.45
0.067

0.887



6
0.232
0.253

1.17

0.59

0.45






7
0.253
0.272
2.73

1.37

1.06


0.040




8
0.272
0.288

1.17

0.59

0.45
0.053

1.332



9
0.288
0.305

1.17

0.59

0.45






10
0.305
0.321
2.73

1.37

1.06


0.033




11
0.321
0.336

1.17

0.59

0.45
0.031

0.951



12
0.336
0.351
2.73

1.37

1.06


0.030




13
0.351
0.365

1.17

0.59

0.45
0.029

0.960



14
0.365
0.378
2.73

1.37

1.06


0.040




15
0.378
0.391

1.17

0.59

0.45
0.039

0.966



16
0.391
0.403

1.17

0.59

0.45






17
0.403
0.416
2.73

1.37

1.06


0.025




18
0.416
0.428

1.17

0.59

0.45
0.024

0.972



19
0.428
0.439
2.73

1.37

1.06


0.034




20
0.439
0.450

1.17

0.59

0.45
0.033

0.975



21
0.450
0.461

1.17

0.59

0.45






22
0.461
0.472
2.73

1.37

1.06


0.022




23
0.472
0.483

1.17

0.59

0.45
0.022

0.978



24
0.483
0.493
2.73

1.37

1.06


0.021




25
0.493
0.503

1.17

0.59

0.45
0.021

0.980



26
0.503
0.513
2.73

1.37

1.06


0.030




27
0.513
0.523

1.17

0.59

0.45
0.029

0.982



28
0.523
0.532

1.17

0.59

0.45






29
0.532
0.542
2.73

1.37

1.06


0.019




30
0.542
0.551

1.17

0.59

0.45
0.019

0.984



31
0.551
0.560
2.73

1.37

1.06


0.019




32
0.560
0.570

1.17

0.59

0.45
0.018

0.984



33
0.570
0.579
2.73

1.37

1.06


0.026




34
0.579
0.587

1.17

0.59

0.45
0.026

0.986



35
0.587
0.596

1.17

0.59

0.45






36
0.596
0.604
2.73

1.37

1.06


0.017




37
0.604
0.613

1.17

0.59

0.45
0.017

0.987



38
0.613
0.621
2.73

1.37

1.06


0.017




39
0.621
0.629

1.17

0.59

0.45
0.017

0.988



40
0.629
0.637
2.73

1.37

1.06


0.016




41
0.637
0.645

1.17

0.59

0.45
0.016

0.988



42
0.645
0.653
2.73

1.37

1.06


0.016




43
0.653
0.661

1.17

0.59

0.45
0.016

0.989



44
0.661
0.669
2.73

1.37

1.06


0.016




45
0.669
0.677

1.17

0.59

0.45
0.016

0.989



46
0.677
0.684
2.73

1.37

1.06


0.022




47
0.684
0.692

1.17

0.59

0.45
0.022

0.990



48
0.692
0.699

1.17

0.59

0.45






49
0.699
0.707
2.73

1.37

1.06


0.015




50
0.707
0.714

1.17

0.59

0.45
0.015

0.991



51
0.714
0.721
2.73

1.37

1.06


0.015




52
0.721
0.728

1.17

0.59

0.45
0.014

0.991



53
0.728
0.736
2.73

1.37

1.06


0.014




54
0.736
0.743

1.17

0.59

0.45
0.014

0.991



55
0.743
0.750
2.73

1.37

1.06


0.014




56
0.750
0.757

1.17

0.59

0.45
0.014

0.991



57
0.757
0.763
2.73

1.37

1.06


0.014




58
0.763
0.770

1.17

0.59

0.45
0.014

0.992



59
0.770
0.777
2.73

1.37

1.06


0.014




60
0.777
0.784

1.17

0.59

0.45
0.014

0.992




























TABLE 36B







First Area
61
0.784
0.791
2.73

1.37

1.06


0.013




62
0.791
0.797

1.17

0.59

0.45
0.013

0.992



63
0.797
0.804
2.73

1.37

1.06


0.013




64
0.804
0.810

1.17

0.59

0.45
0.013

0.992



65
0.810
0.817
2.73

1.37

1.06


0.013




66
0.817
0.823

1.17

0.59

0.45
0.013

0.993



67
0.823
0.830
2.73

1.37

1.06


0.013




68
0.830
0.836

1.17

0.59

0.45
0.013

0.993



69
0.836
0.842
2.73

1.37

1.06


0.013




70
0.842
0.849

1.17

0.59

0.45
0.013

0.993



71
0.849
0.855
2.73

1.37

1.06


0.012




72
0.855
0.861

1.17

0.59

0.45
0.012

0.993



73
0.861
0.867
2.73

1.37

1.06


0.012




74
0.867
0.873

1.17

0.59

0.45
0.012

0.993



75
0.873
0.879
2.73

1.37

1.06


0.012




76
0.879
0.885

1.17

0.59

0.45
0.012

0.994



77
0.885
0.891
2.73

1.37

1.06


0.012




78
0.891
0.897

1.17

0.59

0.45
0.012

0.994



79
0.897
0.903
2.73

1.37

1.06


0.012




80
0.903
0.909

1.17

0.59

0.45
0.012

0.994



81
0.909
0.915
2.73

1.37

1.06


0.012




82
0.915
0.921

1.17

0.59

0.45
0.012

0.994



83
0.921
0.927
2.73

1.37

1.06


0.018




84
0.927
0.932
2.73

1.37

1.06







85
0.932
0.938

1.17

0.59

0.45
0.018

0.994



86
0.938
0.944
2.73

1.37

1.06


0.011




87
0.944
0.949

1.17

0.59

0.45
0.011

0.994



88
0.949
0.955
2.73

1.37

1.06


0.011




89
0.955
0.961

1.17

0.59

0.45
0.011

0.995



90
0.961
0.966
2.73

1.37

1.06


0.011




91
0.966
0.972

1.17

0.59

0.45
0.011

0.994



92
0.972
0.977
2.73

1.37

1.06


0.011




93
0.977
0.983

1.17

0.59

0.45
0.011

0.995



94
0.983
0.988
2.73

1.37

1.06


0.017




95
0.988
0.994
2.73

1.37

1.06







96
0.994
0.999

1.17

0.59

0.45
0.017

0.995



97
0.999
1.005
2.73

1.37

1.06


0.011




98
1.005
1.010

1.17

0.59

0.45
0.011

0.995



99
1.010
1.015
2.73

1.37

1.06


0.011




100
1.015
1.020

1.17

0.59

0.45
0.011

0.995



101
1.020
1.026
2.73

1.37

1.06


0.016




102
1.026
1.031
2.73

1.37

1.06







103
1.031
1.036

1.17

0.59

0.45
0.016

0.995



104
1.036
1.041
2.73

1.37

1.06


0.010




105
1.041
1.047

1.17

0.59

0.45
0.010

0.995



106
1.047
1.052
2.73

1.37

1.06


0.016




107
1.052
1.057
2.73

1.37

1.06







108
1.057
1.062

1.17

0.59

0.45
0.016

0.995



109
1.062
1.067
2.73

1.37

1.06


0.010




110
1.067
1.072

1.17

0.59

0.45
0.010

0.995



111
1.072
1.077
2.73

1.37

1.06


0.015




112
1.077
1.082
2.73

1.37

1.06







113
1.082
1.085

1.17

0.59

0.45
0.015

0.973


Second Area
114
1.085
1.088
2.52

1.26

1.09


0.006




115
1.088
1.093

1.39

0.70

0.61
0.006

0.979



116
1.093
1.097
2.52

1.26

1.09


0.013




117
1.097
1.101

1.39

0.70

0.61
0.013

0.995



118
1.101
1.106

1.39

0.70

0.61






119
1.106
1.110
2.52

1.26

1.09


0.009




120
1.110
1.115

1.39

0.70

0.61
0.009

0.996




























TABLE 36C







Second Area
121
1.115
1.119
2.52

1.26

1.09


0.013




122
1.119
1.123

1.39

0.70

0.61
0.013

0.996



123
1.123
1.127

1.39

0.70

0.61






124
1.127
1.132
2.52

1.26

1.09


0.009




125
1.132
1.136

1.39

0.70

0.61
0.009

0.996



126
1.136
1.140
2.52

1.26

1.09


0.012




127
1.140
1.144

1.39

0.70

0.61
0.012

0.996



128
1.144
1.148

1.39

0.70

0.61






129
1.148
1.153
2.52

1.26

1.09


0.008




130
1.153
1.157

1.39

0.70

0.61
0.008

0.996



131
1.157
1.161
2.52

1.26

1.09


0.012




132
1.161
1.165

1.39

0.70

0.61
0.012

0.997



133
1.165
1.169

1.39

0.70

0.61






134
1.169
1.173
2.52

1.26

1.09


0.008




135
1.173
1.177

1.39

0.70

0.61
0.008

0.997



136
1.177
1.181
2.52

1.26

1.09


0.008




137
1.181
1.185

1.39

0.70

0.61
0.008

0.997



138
1.185
1.190
2.52

1.26

1.09


0.008




139
1.190
1.194

1.39

0.70

0.61
0.008

0.997



140
1.194
1.198
2.52

1.26

1.09


0.008




141
1.198
1.202

1.39

0.70

0.61
0.008

0.997



142
1.202
1.206
2.52

1.26

1.09


0.008




144
1.206
1.210

1.39

0.70

0.61
0.008

0.997



145
1.210
1.214
2.52

1.26

1.09


0.008




146
1.214
1.218

1.39

0.70

0.61
0.008

0.997



147
1.218
1.222
2.52

1.26

1.09


0.008




148
1.222
1.226

1.39

0.70

0.61
0.008

0.998



149
1.226
1.230
2.52

1.26

1.09


0.008




150
1.230
1.234

1.39

0.70

0.61
0.008

0.998



151
1.234
1.238
2.52

1.26

1.09


0.008




152
1.238
1.242

1.39

0.70

0.61
0.008

0.998



153
1.242
1.246
2.52

1.26

1.09


0.008




154
1.246
1.250

1.39

0.70

0.61
0.008

0.998



155
1.250
1.254
2.52

1.26

1.09


0.012




156
1.254
1.258
2.52

1.26

1.09







157
1.258
1.262

1.39

0.70

0.61
0.012

0.998



158
1.262
1.266
2.52

1.26

1.09


0.008




159
1.266
1.270

1.39

0.70

0.61
0.008

0.998



160
1.270
1.274
2.52

1.26

1.09


0.012




161
1.274
1.278
2.52

1.26

1.09







162
1.278
1.282

1.39

0.70

0.61
0.012

0.998



163
1.282
1.286
2.52

1.26

1.09







164
1.286
1.290
2.52

1.26

1.09






Third Area
165
1.290
1.319
4.00

2.00

0.93







166
1.319
1.347
4.00

2.00

0.93







167
1.347
1.373
4.00

2.00

0.93







168
1.373
1.397
4.00

2.00

0.93







169
1.397
1.419
4.00

2.00

0.93







170
1.419
1.439
4.00

2.00

0.93







171
1.439
1.457
4.00

2.00

0.93







172
1.457
1.473
4.00

2.00

0.93







173
1.473
1.488
4.00

2.00

0.93







174
1.488
1.500
4.00

2.00

0.93









Seventh Example
Hereafter, a seventh example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the seventh example are shown in Tables 37 to 41 and 42A to 42C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the seventh example are shown in FIGS. 12A to 12C, respectively.












TABLE 37








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
2.200
2.478
2.549


NA

0.85
0.60
0.53


Magnification

0.00
0.00
0.00





















TABLE 38







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.396
2.330


Objective Lens


1-2
1.471


1-3
1.285


2
−3.805
0.852
0.850
0.551


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 39






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
−11.400







A4
1.58550E−02
−8.08100E−03
−2.83400E−02
1.38100E−01


A6
3.61320E−03
 5.55850E−02
 2.14920E−02
−1.17810E−01 


A8
3.57000E−04
−2.01700E−02
−3.15020E−05
6.90170E−02


A10
−1.95300E−05 
 1.86930E−03
−2.05800E−03
−3.15570E−02 


A12
−1.47730E−05 
−6.12830E−05
 1.54230E−03
1.19050E−02


A14


−6.68900E−04
−4.00170E−03 


A16


 1.56500E−04
1.13430E−03


A18


−1.58740E−05
−2.16810E−04 


A20



1.89670E−05


A22


A24



















TABLE 40





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
4.09880E+01
2.60350E+01
2.60000E+01


P4
−5.83500E+00 
−2.46600E+01 
−3.72670E+01 


P6
6.59200E−01
4.51070E+01
1.61400E+01


P8
7.53000E−02
−1.96000E+01 
−2.39000E+00 


P10
−1.04500E−01 
2.17000E+00
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 41







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.17850E+01
−4.20930E+01



P4
−3.63600E+00
−1.55950E+01



P6
 9.68100E−01
 3.11200E+01



P8
−3.46500E−01
−1.44070E+01



P10
−3.65500E−02
 1.75700E+00



P12
 0.00000E+00
 0.00000E+00




















TABLE 42A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.089












1
0.089
0.146

1.69

0.85

0.61






2
0.146
0.186
2.36

1.18

0.85


0.098




3
0.186
0.219

1.69

0.85

0.61
0.073

0.750



4
0.219
0.249
2.36

1.18

0.85


0.062




5
0.249
0.275

1.69

0.85

0.61
0.056

0.896



6
0.275
0.299
2.36

1.18

0.85


0.050




7
0.299
0.321

1.69

0.85

0.61
0.046

0.911



8
0.321
0.342
2.36

1.18

0.85


0.064




9
0.342
0.363

1.69

0.85

0.61
0.060

0.945



10
0.363
0.381

1.69

0.85

0.61






11
0.381
0.399
2.36

1.18

0.85


0.036




12
0.399
0.416

1.69

0.85

0.61
0.035

0.956



13
0.416
0.432
2.36

1.18

0.85


0.033




14
0.432
0.448

1.69

0.85

0.61
0.032

0.967



15
0.448
0.463
2.36

1.18

0.85


0.031




16
0.463
0.478

1.69

0.85

0.61
0.030

0.966



17
0.478
0.492
2.36

1.18

0.85


0.029




18
0.492
0.506

1.69

0.85

0.61
0.028

0.971



19
0.506
0.519
2.36

1.18

0.85


0.027




20
0.519
0.533

1.69

0.85

0.61
0.027

0.979



21
0.533
0.546
2.36

1.18

0.85


0.040




22
0.546
0.559

1.69

0.85

0.61
0.039

0.975



23
0.559
0.572

1.69

0.85

0.61






24
0.572
0.584
2.36

1.18

0.85


0.024




25
0.584
0.596

1.69

0.85

0.61
0.024

0.985



26
0.596
0.607
2.36

1.18

0.85


0.023




27
0.607
0.619

1.69

0.85

0.61
0.023

0.985



28
0.619
0.630
2.36

1.18

0.85


0.023




29
0.630
0.641

1.69

0.85

0.61
0.022

0.983



30
0.641
0.652
2.36

1.18

0.85


0.022




31
0.652
0.663

1.69

0.85

0.61
0.022

0.982



32
0.663
0.673
2.36

1.18

0.85


0.021




33
0.673
0.684

1.69

0.85

0.61
0.021

0.983



34
0.684
0.694
2.36

1.18

0.85


0.021




35
0.694
0.704

1.69

0.85

0.61
0.020

0.986



36
0.704
0.714
2.36

1.18

0.85


0.020




37
0.714
0.724

1.69

0.85

0.61
0.020

0.987



38
0.724
0.734
2.36

1.18

0.85


0.020




39
0.734
0.743

1.69

0.85

0.61
0.019

0.989



40
0.743
0.753
2.36

1.18

0.85


0.019




41
0.753
0.762

1.69

0.85

0.61
0.019

0.989



42
0.762
0.771
2.36

1.18

0.85


0.019




43
0.771
0.781

1.69

0.85

0.61
0.019

0.990



44
0.781
0.790
2.36

1.18

0.85


0.018




45
0.790
0.799

1.69

0.85

0.61
0.018

0.990



46
0.799
0.808
2.36

1.18

0.85


0.018




47
0.808
0.816

1.69

0.85

0.61
0.018

0.990



48
0.816
0.825
2.36

1.18

0.85


0.018




49
0.825
0.834

1.69

0.85

0.61
0.017

0.989



50
0.834
0.842
2.36

1.18

0.85


0.017




51
0.842
0.851

1.69

0.85

0.61
0.017

0.989



52
0.851
0.859
2.36

1.18

0.85


0.017




53
0.859
0.868

1.69

0.85

0.61
0.017

0.990



54
0.868
0.876
2.36

1.18

0.85


0.017




55
0.876
0.884

1.69

0.85

0.61
0.016

0.992



56
0.884
0.892
2.36

1.18

0.85


0.024




57
0.892
0.900
2.36

1.18

0.85







58
0.900
0.908

1.69

0.85

0.61
0.024

0.993



59
0.908
0.916
2.36

1.18

0.85


0.016




60
0.916
0.924

1.69

0.85

0.61
0.016

0.992




























TABLE 42B







First Area
61
0.924
0.931
2.36

1.18

0.85


0.016




62
0.931
0.939

1.69

0.85

0.61
0.016

0.993



63
0.939
0.947
2.36

1.18

0.85


0.015




64
0.947
0.955

1.69

0.85

0.61
0.015

0.993



65
0.955
0.962
2.36

1.18

0.85


0.015




66
0.962
0.970

1.69

0.85

0.61
0.015

0.992



67
0.970
0.977
2.36

1.18

0.85


0.015




68
0.977
0.985

1.69

0.85

0.61
0.015

0.992



69
0.985
0.991
2.36

1.18

0.85


0.022




70
0.991
0.999
2.36

1.18

0.85







71
0.999
1.006

1.69

0.85

0.61
0.022

0.989



72
1.006
1.013
2.36

1.18

0.85


0.014




73
1.013
1.021

1.69

0.85

0.61
0.014

1.002



74
1.021
1.028
2.36

1.18

0.85


0.014




75
1.028
1.035

1.69

0.85

0.61
0.014

0.995



76
1.035
1.042
2.36

1.18

0.85


0.014




77
1.042
1.049

1.69

0.85

0.61
0.014

0.996



78
1.049
1.056
2.36

1.18

0.85


0.014




79
1.056
1.063

1.69

0.85

0.61
0.014

0.991



80
1.063
1.069
2.36

1.18

0.85


0.020




81
1.069
1.076
2.36

1.18

0.85







82
1.076
1.083

1.69

0.85

0.61
0.020

0.996



83
1.083
1.090
2.36

1.18

0.85


0.014




84
1.090
1.097

1.69

0.85

0.61
0.014

0.992



85
1.097
1.103
2.36

1.18

0.85


0.013




86
1.103
1.110

1.69

0.85

0.61
0.013

0.996



87
1.110
1.116
2.36

1.18

0.85


0.019




88
1.116
1.123
2.36

1.18

0.85







89
1.123
1.129

1.69

0.85

0.61
0.019

0.995



90
1.129
1.136
2.36

1.18

0.85


0.013




91
1.136
1.142

1.69

0.85

0.61
0.013

0.994



92
1.142
1.148
2.36

1.18

0.85


0.019




93
1.148
1.155
2.36

1.18

0.85







94
1.155
1.161

1.69

0.85

0.61
0.019

0.995



95
1.161
1.168
2.36

1.18

0.85


0.013




96
1.168
1.174

1.69

0.85

0.61
0.013

0.999



97
1.174
1.180
2.36

1.18

0.85


0.019




98
1.180
1.186
2.36

1.18

0.85







99
1.186
1.194

1.69

0.85

0.61
0.019

1.019


Second Area
100
1.194
1.200

1.32

0.66

0.52






101
1.200
1.206
2.46

1.23

0.96


0.031




102
1.206
1.212
2.46

1.23

0.96







103
1.212
1.217

1.32

0.66

0.52
0.029

0.965



104
1.217
1.222

1.32

0.66

0.52






105
1.222
1.228
2.46

1.23

0.96


0.011




106
1.228
1.234

1.32

0.66

0.52
0.011

0.995



107
1.234
1.239
2.46

1.23

0.96


0.016




108
1.239
1.244

1.32

0.66

0.52
0.016

0.995



109
1.244
1.249

1.32

0.66

0.52






110
1.249
1.255
2.46

1.23

0.96


0.011




111
1.255
1.260

1.32

0.66

0.52
0.011

0.995



112
1.260
1.266
2.46

1.23

0.96


0.015




113
1.266
1.270

1.32

0.66

0.52
0.015

0.995



114
1.270
1.275

1.32

0.66

0.52






115
1.275
1.281
2.46

1.23

0.96


0.011




116
1.281
1.286

1.32

0.66

0.52
0.011

0.995



117
1.286
1.292
2.46

1.23

0.96


0.011




118
1.292
1.297

1.32

0.66

0.52
0.011

0.995



119
1.297
1.302
2.46

1.23

0.96


0.011




120
1.302
1.307

1.32

0.66

0.52
0.011

0.996




























TABLE 42C







Second Area
121
1.307
1.313
2.46

1.23

0.96


0.010




122
1.313
1.318

1.32

0.66

0.52
0.010

0.996



123
1.318
1.323
2.46

1.23

0.96


0.010




124
1.323
1.328

1.32

0.66

0.52
0.010

0.996



125
1.328
1.333
2.46

1.23

0.96


0.010




126
1.333
1.338

1.32

0.66

0.52
0.010

0.996



127
1.338
1.343
2.46

1.23

0.96


0.010




128
1.343
1.349

1.32

0.66

0.52
0.010

0.996



129
1.349
1.354
2.46

1.23

0.96


0.010




130
1.354
1.359

1.32

0.66

0.52
0.010

0.996



131
1.359
1.365
2.46

1.23

0.96







132
1.365
1.370
2.46

1.23

0.96


0.016




133
1.370
1.375

1.32

0.66

0.52
0.016

0.996



134
1.375
1.380
2.46

1.23

0.96







135
1.380
1.385
2.46

1.23

0.96


0.016




136
1.385
1.390

1.32

0.66

0.52
0.016

0.996



137
1.390
1.396
2.46

1.23

0.96







138
1.396
1.401
2.46

1.23

0.96


0.016




139
1.401
1.406

1.32

0.66

0.52
0.016

0.997



140
1.406
1.412
2.46

1.23

0.96


0.021




141
1.412
1.417
2.46

1.23

0.96







142
1.417
1.422
2.46

1.23

0.96







144
1.422
1.427

1.32

0.66

0.52
0.021

0.997



145
1.427
1.433
2.46

1.23

0.96







146
1.433
1.438
2.46

1.23

0.96







147
1.438
1.444
2.46

1.23

0.96







148
1.444
1.449
2.46

1.23

0.96







149
1.449
1.455
2.46

1.23

0.96







150
1.455
1.461
2.46

1.23

0.96







151
1.461
1.466
2.46

1.23

0.96







152
1.466
1.472
2.46

1.23

0.96







153
1.472
1.477
2.46

1.23

0.96







154
1.477
1.480
2.46

1.23

0.96






Third Area
155
1.480
1.496
4.00

2.00

0.83







156
1.496
1.553
4.00

2.00

0.83







157
1.553
1.598
4.00

2.00

0.83







158
1.598
1.634
4.00

2.00

0.83







159
1.634
1.662
4.00

2.00

0.83







160
1.662
1.685
4.00

2.00

0.83







161
1.685
1.704
4.00

2.00

0.83







162
1.704
1.721
4.00

2.00

0.83







163
1.721
1.736
4.00

2.00

0.83







164
1.736
1.749
4.00

2.00

0.83







165
1.749
1.761
4.00

2.00

0.83







166
1.761
1.773
4.00

2.00

0.83







167
1.773
1.783
4.00

2.00

0.83







168
1.783
1.792
4.00

2.00

0.83







169
1.792
1.801
4.00

2.00

0.83







170
1.801
1.809
4.00

2.00

0.83







171
1.809
1.817
4.00

2.00

0.83







172
1.817
1.824
4.00

2.00

0.83







173
1.824
1.831
4.00

2.00

0.83







174
1.831
1.838
4.00

2.00

0.83







175
1.838
1.844
4.00

2.00

0.83







176
1.844
1.850
4.00

2.00

0.83







177
1.850
1.856
4.00

2.00

0.83







178
1.856
1.862
4.00

2.00

0.83







179
1.862
1.870
4.00

2.00

0.83









Eighth Example
Hereafter, an eighth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the eighth example are shown in Tables 43 to 47 and 48A to 48E. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the eighth example are shown in FIGS. 13A to 13C, respectively.












TABLE 43








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.411
1.725
1.816


NA

0.85
0.62
0.50


Magnification

0.00
0.00
0.00





















TABLE 44







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
0.892
1.620


Objective Lens


1-2
1.091


1-3
0.846


2
−1.995
0.472
0.561
0.300


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 45






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
2.530







A4
1.06300E−02
2.37900E−02
−8.10650E−02
8.79500E−01


A6
1.16300E−01
4.64850E−01
 1.78440E−01
−1.68920E+00 


A8
−5.38300E−02 
−3.86200E−01 
−8.42660E−02
2.44100E+00


A10
1.86360E−02
9.25250E−02
 1.37550E−01
−2.33130E+00 


A12
9.35300E−04
1.95180E−03
−1.74190E−01
1.17130E+00


A14


 1.14750E−01
2.75770E−01


A16


−3.17440E−02
−7.30160E−01 


A18



3.05960E−01


A20


A22


A24



















TABLE 46





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
1.31760E+02
4.80410E+01
3.59910E+01


P4
−7.22670E+01 
−5.06860E+01 
−1.18000E+02 


P6
9.40900E+01
3.81670E+02
1.19250E+02


P8
−5.88100E+01 
−3.67390E+02 
−4.22000E+01 


P10
1.75610E+01
1.02040E+02
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 47







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−1.01940E+02
−1.59650E+02



P4
−2.93900E+01
−2.77000E+00



P6
 5.05270E+01
 2.41900E+02



P8
−5.20050E+01
−2.85380E+02



P10
 1.32420E+01
 8.70170E+01



P12
 0.00000E+00
 0.00000E+00




















TABLE 48A








Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4






















First Area
0
0.000
0.049












1
0.049
0.081

1.43

0.72

0.52






2
0.081
0.103
2.52

1.26

0.91


0.054




3
0.103
0.123

1.43

0.72

0.52
0.042

0.777



4
0.123
0.139
2.52

1.26

0.91


0.036




5
0.139
0.154

1.43

0.72

0.52
0.031

0.864



6
0.154
0.167
2.52

1.26

0.91


0.028




7
0.167
0.180

1.43

0.72

0.52
0.026

0.926



8
0.180
0.192
2.52

1.26

0.91


0.035




9
0.192
0.202

1.43

0.72

0.52
0.033

0.939



10
0.202
0.213

1.43

0.72

0.52






11
0.213
0.223
2.52

1.26

0.91


0.021




12
0.223
0.232

1.43

0.72

0.52
0.020

0.952



13
0.232
0.241
2.52

1.26

0.91


0.019




14
0.241
0.250

1.43

0.72

0.52
0.018

0.957



15
0.250
0.259
2.52

1.26

0.91


0.018




16
0.259
0.267

1.43

0.72

0.52
0.017

0.970



17
0.267
0.275
2.52

1.26

0.91


0.016




18
0.275
0.283

1.43

0.72

0.52
0.016

0.975



19
0.283
0.291
2.52

1.26

0.91


0.016




20
0.291
0.298

1.43

0.72

0.52
0.015

0.974



21
0.298
0.306
2.52

1.26

0.91


0.022




22
0.306
0.313

1.43

0.72

0.52
0.021

0.977



23
0.313
0.320

1.43

0.72

0.52






24
0.320
0.326
2.52

1.26

0.91


0.014




25
0.326
0.333

1.43

0.72

0.52
0.014

0.981



26
0.333
0.340
2.52

1.26

0.91


0.013




27
0.340
0.346

1.43

0.72

0.52
0.013

0.979



28
0.346
0.353
2.52

1.26

0.91


0.013




29
0.353
0.359

1.43

0.72

0.52
0.013

0.980



30
0.359
0.365
2.52

1.26

0.91


0.012




31
0.365
0.371

1.43

0.72

0.52
0.012

0.983



32
0.371
0.377
2.52

1.26

0.91


0.012




33
0.377
0.383

1.43

0.72

0.52
0.012

0.986



34
0.383
0.389
2.52

1.26

0.91


0.012




35
0.389
0.395

1.43

0.72

0.52
0.012

0.988



36
0.395
0.400
2.52

1.26

0.91


0.011




37
0.400
0.406

1.43

0.72

0.52
0.011

0.988



38
0.406
0.411
2.52

1.26

0.91


0.011




39
0.411
0.417

1.43

0.72

0.52
0.011

0.987



40
0.417
0.422
2.52

1.26

0.91


0.011




41
0.422
0.427

1.43

0.72

0.52
0.011

0.986



42
0.427
0.433
2.52

1.26

0.91


0.011




43
0.433
0.438

1.43

0.72

0.52
0.010

0.986



44
0.438
0.443
2.52

1.26

0.91


0.010




45
0.443
0.448

1.43

0.72

0.52
0.010

0.987



46
0.448
0.453
2.52

1.26

0.91


0.010




47
0.453
0.458

1.43

0.72

0.52
0.010

0.988



48
0.458
0.463
2.52

1.26

0.91


0.010




49
0.463
0.468

1.43

0.72

0.52
0.010

0.990



50
0.468
0.473
2.52

1.26

0.91


0.010




51
0.473
0.477

1.43

0.72

0.52
0.010

0.992



52
0.477
0.482
2.52

1.26

0.91


0.009




53
0.482
0.487

1.43

0.72

0.52
0.009

0.993



54
0.487
0.491
2.52

1.26

0.91


0.009




55
0.491
0.496

1.43

0.72

0.52
0.009

0.993



56
0.496
0.501
2.52

1.26

0.91


0.009




57
0.501
0.505

1.43

0.72

0.52
0.009

0.992



58
0.505
0.510
2.52

1.26

0.91


0.009




59
0.510
0.514

1.43

0.72

0.52
0.009

0.992



60
0.514
0.518
2.52

1.26

0.91


0.009




























TABLE 48B







First Area
61
0.518
0.523

1.43

0.72

0.52
0.009

0.991



62
0.523
0.527
2.52

1.26

0.91


0.009



63
0.527
0.531

1.43

0.72

0.52
0.009

0.990



64
0.531
0.536
2.52

1.26

0.91


0.009



65
0.536
0.540

1.43

0.72

0.52
0.009

0.991



66
0.540
0.544
2.52

1.26

0.91


0.008



67
0.544
0.548

1.43

0.72

0.52
0.008

0.991



68
0.548
0.552
2.52

1.26

0.91


0.008



69
0.552
0.557

1.43

0.72

0.52
0.008

0.992



70
0.557
0.561
2.52

1.26

0.91


0.008



71
0.561
0.565

1.43

0.72

0.52
0.008

0.993



72
0.565
0.569
2.52

1.26

0.91


0.008



73
0.569
0.573

1.43

0.72

0.52
0.008

0.994



74
0.573
0.577
2.52

1.26

0.91


0.008



75
0.577
0.581

1.43

0.72

0.52
0.008

0.995



76
0.581
0.585
2.52

1.26

0.91


0.008



77
0.585
0.588

1.43

0.72

0.52
0.008

0.995



78
0.588
0.592
2.52

1.26

0.91


0.008



79
0.592
0.596

1.43

0.72

0.52
0.008

0.994



80
0.596
0.600
2.52

1.26

0.91


0.008



81
0.600
0.604

1.43

0.72

0.52
0.008

0.993



82
0.604
0.608
2.52

1.26

0.91


0.008



83
0.608
0.611

1.43

0.72

0.52
0.008

0.993



84
0.611
0.615
2.52

1.26

0.91


0.007



85
0.615
0.619

1.43

0.72

0.52
0.007

0.992



86
0.619
0.622
2.52

1.26

0.91


0.007



87
0.622
0.626

1.43

0.72

0.52
0.007

0.993



88
0.626
0.630
2.52

1.26

0.91


0.007



89
0.630
0.633

1.43

0.72

0.52
0.007

0.993



90
0.633
0.637
2.52

1.26

0.91


0.007



91
0.637
0.640

1.43

0.72

0.52
0.007

0.994



92
0.640
0.644
2.52

1.26

0.91


0.007



93
0.644
0.648

1.43

0.72

0.52
0.007

0.995



94
0.648
0.651
2.52

1.26

0.91


0.007



95
0.651
0.655

1.43

0.72

0.52
0.007

0.995



96
0.655
0.658
2.52

1.26

0.91


0.007



97
0.658
0.661

1.43

0.72

0.52
0.007

0.996



98
0.661
0.665
2.52

1.26

0.91


0.007



99
0.665
0.668

1.43

0.72

0.52
0.007

0.995



100
0.668
0.672
2.52

1.26

0.91


0.010



101
0.672
0.675
2.52

1.26

0.91



102
0.675
0.679

1.43

0.72

0.52
0.010

1.009



103
0.679
0.682
2.52

1.26

0.91


0.007



104
0.682
0.685

1.43

0.72

0.52
0.007

0.971



105
0.685
0.688
2.52

1.26

0.91


0.007



106
0.688
0.692

1.43

0.72

0.52
0.007

0.996



107
0.692
0.695
2.52

1.26

0.91


0.007



108
0.695
0.698

1.43

0.72

0.52
0.006

0.995



109
0.698
0.701
2.52

1.26

0.91


0.006



110
0.701
0.705

1.43

0.72

0.52
0.006

0.994



111
0.705
0.708
2.52

1.26

0.91


0.006



112
0.708
0.711

1.43

0.72

0.52
0.006

0.994



113
0.711
0.714
2.52

1.26

0.91


0.006



114
0.714
0.717

1.43

0.72

0.52
0.006

0.994



115
0.717
0.720
2.52

1.26

0.91


0.006



116
0.720
0.724

1.43

0.72

0.52
0.006

0.995



117
0.724
0.727
2.52

1.26

0.91


0.006



118
0.727
0.730

1.43

0.72

0.52
0.006

0.996



119
0.730
0.733
2.52

1.26

0.91


0.006



120
0.733
0.736

1.43

0.72

0.52
0.006

0.996




























TABLE 48C







First Area
121
0.736
0.739
2.52

1.26

0.91


0.006




122
0.739
0.742

1.43

0.72

0.52
0.006

0.995



123
0.742
0.745
2.52

1.26

0.91


0.006



124
0.745
0.748

1.43

0.72

0.52
0.006

0.994



125
0.748
0.751
2.52

1.26

0.91


0.009



126
0.751
0.754
2.52

1.26

0.91



127
0.754
0.757

1.43

0.72

0.52
0.009

0.995



128
0.757
0.760
2.52

1.26

0.91


0.006



129
0.760
0.763

1.43

0.72

0.52
0.006

0.996



130
0.763
0.766
2.52

1.26

0.91


0.006



131
0.766
0.768

1.43

0.72

0.52
0.006

0.995



132
0.768
0.771
2.52

1.26

0.91


0.006



133
0.771
0.774

1.43

0.72

0.52
0.006

0.994



134
0.774
0.777
2.52

1.26

0.91


0.006



135
0.777
0.780

1.43

0.72

0.52
0.006

0.994



136
0.780
0.783
2.52

1.26

0.91


0.006



137
0.783
0.785

1.43

0.72

0.52
0.006

0.995



138
0.785
0.788
2.52

1.26

0.91


0.006



139
0.788
0.791

1.43

0.72

0.52
0.006

0.996



140
0.791
0.794
2.52

1.26

0.91


0.006



141
0.794
0.797

1.43

0.72

0.52
0.006

0.996



142
0.797
0.799
2.52

1.26

0.91


0.005



143
0.799
0.802

1.43

0.72

0.52
0.005

0.995



144
0.802
0.805
2.52

1.26

0.91


0.008



145
0.805
0.807
2.52

1.26

0.91



146
0.807
0.810

1.43

0.72

0.52
0.008

0.995



147
0.810
0.813
2.52

1.26

0.91


0.005



148
0.813
0.815

1.43

0.72

0.52
0.005

0.996



149
0.815
0.818
2.52

1.26

0.91


0.005



150
0.818
0.821

1.43

0.72

0.52
0.005

0.994



151
0.821
0.823
2.52

1.26

0.91


0.005



152
0.823
0.826

1.43

0.72

0.52
0.005

0.994



153
0.826
0.829
2.52

1.26

0.91


0.005



154
0.829
0.831

1.43

0.72

0.52
0.005

0.995



155
0.831
0.834
2.52

1.26

0.91


0.005



156
0.834
0.836

1.43

0.72

0.52
0.005

0.997



157
0.836
0.839
2.52

1.26

0.91


0.005



158
0.839
0.841

1.43

0.72

0.52
0.005

0.996



159
0.841
0.844
2.52

1.26

0.91


0.008



160
0.844
0.847
2.52

1.26

0.91



161
0.847
0.849

1.43

0.72

0.52
0.008

0.995



162
0.849
0.851
2.52

1.26

0.91


0.005



163
0.851
0.854

1.43

0.72

0.52
0.005

0.996



164
0.854
0.856
2.52

1.26

0.91


0.005



165
0.856
0.859

1.43

0.72

0.52
0.005

0.994



166
0.859
0.861
2.52

1.26

0.91


0.005



167
0.861
0.864

1.43

0.72

0.52
0.005

0.995



168
0.864
0.866
2.52

1.26

0.91


0.005



169
0.866
0.869

1.43

0.72

0.52
0.005

0.997



170
0.869
0.871
2.52

1.26

0.91


0.005



171
0.871
0.873

1.43

0.72

0.52
0.005

0.997



172
0.873
0.876
2.52

1.26

0.91


0.005



173
0.876
0.878

1.43

0.72

0.52
0.005

0.993



174
0.878
0.881
2.52

1.26

0.91


0.007



175
0.881
0.883
2.52

1.26

0.91



176
0.883
0.885

1.43

0.72

0.52
0.007

0.996



177
0.885
0.888
2.52

1.26

0.91


0.005



178
0.888
0.890

1.43

0.72

0.52
0.005

0.994



179
0.890
0.892
2.52

1.26

0.91


0.005



180
0.892
0.895

1.43

0.72

0.52
0.005

0.999




























TABLE 48D







First Area
181
0.895
0.897
2.52

1.26

0.91


0.005




182
0.897
0.899

1.43

0.72

0.52
0.005

0.992



183
0.899
0.901
2.52

1.26

0.91


0.005



184
0.901
0.904

1.43

0.72

0.52
0.005

1.001



185
0.904
0.906
2.52

1.26

0.91


0.004



186
0.906
0.908

1.43

0.72

0.52
0.004

0.993



187
0.908
0.910
2.52

1.26

0.91


0.010


Second Area
188
0.910
0.911
2.41

1.21

1.01



189
0.911
0.913
2.41

1.21

1.01



190
0.913
0.916

1.59

0.79

0.68
0.010

0.981



191
0.916
0.918

1.59

0.79

0.68



192
0.918
0.920
2.41

1.21

1.01


0.004



193
0.920
0.922

1.59

0.79

0.68
0.004

0.997



194
0.922
0.924
2.41

1.21

1.01


0.004



195
0.924
0.926

1.59

0.79

0.68
0.004

0.997



196
0.926
0.928
2.41

1.21

1.01


0.006



197
0.928
0.930

1.59

0.79

0.68
0.006

0.997



198
0.930
0.932

1.59

0.79

0.68



199
0.932
0.934
2.41

1.21

1.01


0.004



200
0.934
0.936

1.59

0.79

0.68
0.004

0.997



201
0.936
0.938
2.41

1.21

1.01


0.004



202
0.938
0.940

1.59

0.79

0.68
0.004

0.997



203
0.940
0.942
2.41

1.21

1.01


0.004



204
0.942
0.944

1.59

0.79

0.68
0.004

0.963



205
0.944
0.946
2.41

1.21

1.01


0.006



206
0.946
0.948

1.59

0.79

0.68
0.006

1.019



207
0.948
0.949

1.59

0.79

0.68



208
0.949
0.951
2.41

1.21

1.01


0.004



209
0.951
0.953

1.59

0.79

0.68
0.004

0.997



210
0.953
0.955
2.41

1.21

1.01


0.004



211
0.955
0.957

1.59

0.79

0.68
0.004

0.997



212
0.957
0.959
2.41

1.21

1.01


0.004



213
0.959
0.961

1.59

0.79

0.68
0.004

0.997



214
0.961
0.963
2.41

1.21

1.01


0.004



215
0.963
0.965

1.59

0.79

0.68
0.004

0.997



216
0.965
0.967
2.41

1.21

1.01


0.004



217
0.967
0.969

1.59

0.79

0.68
0.004

0.997



218
0.969
0.970
2.41

1.21

1.01


0.004



219
0.970
0.972

1.59

0.79

0.68
0.004

0.997



220
0.972
0.974
2.41

1.21

1.01


0.004



221
0.974
0.976

1.59

0.79

0.68
0.004

0.994



222
0.976
0.978
2.41

1.21

1.01


0.004



223
0.978
0.980

1.59

0.79

0.68
0.004

1.012



224
0.980
0.982
2.41

1.21

1.01


0.004



225
0.982
0.984

1.59

0.79

0.68
0.004

0.973



226
0.984
0.986
2.41

1.21

1.01


0.004



227
0.986
0.987

1.59

0.79

0.68
0.004

0.974



228
0.987
0.989
2.41

1.21

1.01


0.003



229
0.989
0.991

1.59

0.79

0.68
0.004

1.044



230
0.991
0.993
2.41

1.21

1.01


0.004



231
0.993
0.994

1.59

0.79

0.68
0.004

0.989



232
0.994
0.996
2.41

1.21

1.01


0.004



233
0.996
0.998

1.59

0.79

0.68
0.004

0.997



234
0.998
1.000
2.41

1.21

1.01


0.004



235
1.000
1.002

1.59

0.79

0.68
0.004

0.997



236
1.002
1.003
2.41

1.21

1.01


0.004



237
1.003
1.005

1.59

0.79

0.68
0.004

0.997



238
1.005
1.007
2.41

1.21

1.01


0.004



239
1.007
1.009

1.59

0.79

0.68
0.004

0.998



240
1.009
1.011
2.41

1.21

1.01


0.004




























TABLE 48E







Second Area
241
1.011
1.012

1.59

0.79

0.68
0.004

0.998



242
1.012
1.014
2.41

1.21

1.01


0.004



243
1.014
1.016

1.59

0.79

0.68
0.004

0.998



244
1.016
1.018
2.41

1.21

1.01


0.005



245
1.018
1.020
2.41

1.21

1.01



246
1.020
1.021

1.59

0.79

0.68
0.005

0.984



247
1.021
1.023
2.41

1.21

1.01


0.003



248
1.023
1.025

1.59

0.79

0.68
0.003

1.019



249
1.025
1.026
2.41

1.21

1.01


0.003



250
1.026
1.028

1.59

0.79

0.68
0.003

0.998



251
1.028
1.030
2.41

1.21

1.01


0.003



252
1.030
1.032

1.59

0.79

0.68
0.003

0.998



253
1.032
1.033
2.41

1.21

1.01


0.005



254
1.033
1.035
2.41

1.21

1.01



255
1.035
1.037

1.59

0.79

0.68
0.005

0.997



256
1.037
1.038
2.41

1.21

1.01


0.003



257
1.038
1.040

1.59

0.79

0.68
0.003

0.998



258
1.040
1.042
2.41

1.21

1.01


0.005



259
1.042
1.044
2.41

1.21

1.01



260
1.044
1.045

1.59

0.79

0.68
0.005

1.005



261
1.045
1.047
2.41

1.21

1.01


0.003



262
1.047
1.049

1.59

0.79

0.68
0.003

0.986



263
1.049
1.050
2.41

1.21

1.01


0.005



264
1.050
1.052
2.41

1.21

1.01



265
1.052
1.054

1.59

0.79

0.68
0.005

0.992



266
1.054
1.055
2.41

1.21

1.01


0.003



267
1.055
1.057

1.59

0.79

0.68
0.003

1.007



268
1.057
1.059
2.41

1.21

1.01


0.005



269
1.059
1.060
2.41

1.21

1.01



270
1.060
1.062

1.59

0.79

0.68
0.005

0.998



271
1.062
1.064
2.41

1.21

1.01


0.003



272
1.064
1.065

1.59

0.79

0.68
0.003

0.998



273
1.065
1.067
2.41

1.21

1.01


0.005



274
1.067
1.069
2.41

1.21

1.01



275
1.069
1.070

1.59

0.79

0.68
0.005

0.957


Third Area
277
1.070
1.082
4.00

2.00

0.89



278
1.082
1.102
4.00

2.00

0.89



279
1.102
1.118
4.00

2.00

0.89



280
1.118
1.132
4.00

2.00

0.89



281
1.132
1.144
4.00

2.00

0.89



282
1.144
1.155
4.00

2.00

0.89



283
1.155
1.164
4.00

2.00

0.89



284
1.164
1.173
4.00

2.00

0.89



285
1.173
1.181
4.00

2.00

0.89



286
1.181
1.188
4.00

2.00

0.89



287
1.188
1.195
4.00

2.00

0.89



288
1.195
1.200
4.00

2.00

0.89









Ninth Example
Hereafter, a ninth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the ninth example are shown in Tables 49 to 53 and 54A to 54C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the ninth example are shown in FIGS. 14A to 14C, respectively.












TABLE 49








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.766
1.990
2.053


NA

0.85
0.63
0.50


Magnification

0.00
−0.02
−0.02





















TABLE 50







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.108
1.880


Objective Lens


1-2
1.102


1-3
1.025


2
−2.937
0.674
0.653
0.300


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 51






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.200







A4
2.83360E−02
−1.51150E−01 
−5.93860E−02
 3.61590E−01


A6
1.30700E−02
2.91900E−01
 7.13160E−02
−5.82660E−01


A8
−1.06700E−03 
−1.31750E−01 
−2.57600E−02
 9.37290E−01


A10
−1.56400E−04 
1.50760E−02
 2.85390E−02
−1.10070E+00


A12
2.76500E−04
1.57040E−03
−2.35650E−02
 8.43450E−01


A14


 1.00810E−02
−3.94430E−01


A16


−1.72670E−03
 1.02050E−01


A18



−1.10800E−02


A20


A22


A24



















TABLE 52





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
5.83490E+01
6.03610E+01
3.63520E+01


P4
−1.51940E+01 
−1.65500E+02 
−7.49400E+01 


P6
7.30800E+00
2.59240E+02
4.82750E+01


P8
−3.65700E+00 
−1.40080E+02 
−1.04240E+01 


P10
2.43600E−01
2.41850E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 53







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.61920E+01
−3.48050E+01



P4
−7.44800E+00
−1.05800E+02



P6
 1.55500E+00
 1.68820E+02



P8
−1.22400E+00
−9.36340E+01



P10
−8.39900E−02
 1.65270E+01



P12
 0.00000E+00
 0.00000E+00





















TABLE 54A









Phase














Difference

Step Height

















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
Annular Zone Pitch




















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P1
P2
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
P3
P4
P3/P4























First Area
0
0.000
0.069












1
0.069
0.126

1.35

0.67

0.49



2
0.126
0.164
2.41

1.21

0.87


0.094



3
0.164
0.194

1.35

0.67

0.49
0.068

0.723



4
0.194
0.221
2.41

1.21

0.87


0.077



5
0.221
0.241

1.35

0.67

0.49
0.068

0.889



6
0.241
0.263

1.35

0.67

0.49



7
0.263
0.283
2.41

1.21

0.87


0.042



8
0.283
0.302

1.35

0.67

0.49
0.040

0.937



9
0.302
0.321
2.41

1.21

0.87


0.050



10
0.321
0.334

1.35

0.67

0.49
0.048

0.947



11
0.334
0.350

1.35

0.67

0.49



12
0.350
0.366
2.41

1.21

0.87


0.032



13
0.366
0.381

1.35

0.67

0.49
0.031

0.956



14
0.381
0.395
2.41

1.21

0.87


0.040



15
0.395
0.406

1.35

0.67

0.49
0.039

0.961



16
0.406
0.420

1.35

0.67

0.49



17
0.420
0.433
2.41

1.21

0.87


0.027



18
0.433
0.446

1.35

0.67

0.49
0.026

0.973



19
0.446
0.458
2.41

1.21

0.87


0.025



20
0.458
0.470

1.35

0.67

0.49
0.025

0.970



21
0.470
0.482
2.41

1.21

0.87


0.033



22
0.482
0.491

1.35

0.67

0.49
0.032

0.979



23
0.491
0.502

1.35

0.67

0.49



24
0.502
0.514
2.41

1.21

0.87


0.022



25
0.514
0.524

1.35

0.67

0.49
0.022

0.978



26
0.524
0.535
2.41

1.21

0.87


0.021



27
0.535
0.545

1.35

0.67

0.49
0.021

0.984



28
0.545
0.556
2.41

1.21

0.87


0.028



29
0.556
0.563

1.35

0.67

0.49
0.028

0.978



30
0.563
0.573

1.35

0.67

0.49



31
0.573
0.583
2.41

1.21

0.87


0.020



32
0.583
0.593

1.35

0.67

0.49
0.019

0.988



33
0.593
0.602
2.41

1.21

0.87


0.019



34
0.602
0.611

1.35

0.67

0.49
0.019

0.982



35
0.611
0.620
2.41

1.21

0.87


0.018



36
0.620
0.629

1.35

0.67

0.49
0.018

0.981



37
0.629
0.638
2.41

1.21

0.87


0.018



38
0.638
0.647

1.35

0.67

0.49
0.018

0.984



39
0.647
0.656
2.41

1.21

0.87


0.017



40
0.656
0.664

1.35

0.67

0.49
0.017

0.990



41
0.664
0.672
2.41

1.21

0.87


0.023



42
0.672
0.679

1.35

0.67

0.49
0.023

0.986



43
0.679
0.687

1.35

0.67

0.49



44
0.687
0.695
2.41

1.21

0.87


0.016



45
0.695
0.703

1.35

0.67

0.49
0.016

0.989



46
0.703
0.711
2.41

1.21

0.87


0.016



47
0.711
0.719

1.35

0.67

0.49
0.016

0.992



48
0.719
0.727
2.41

1.21

0.87


0.016



49
0.727
0.734

1.35

0.67

0.49
0.015

0.991



50
0.734
0.742
2.41

1.21

0.87


0.015



51
0.742
0.750

1.35

0.67

0.49
0.015

0.990



52
0.750
0.757
2.41

1.21

0.87


0.015



53
0.757
0.764

1.35

0.67

0.49
0.015

0.989



54
0.764
0.772
2.41

1.21

0.87


0.015



55
0.772
0.779

1.35

0.67

0.49
0.014

0.989



56
0.779
0.786
2.41

1.21

0.87


0.014



57
0.786
0.793

1.35

0.67

0.49
0.014

0.989



58
0.793
0.800
2.41

1.21

0.87


0.014



59
0.800
0.807

1.35

0.67

0.49
0.014

0.990



60
0.807
0.814
2.41

1.21

0.87


0.014




























TABLE 54B







First Area
61
0.814
0.821

1.35

0.67

0.49
0.014

0.990



62
0.821
0.827
2.41

1.21

0.87


0.014



63
0.827
0.834

1.35

0.67

0.49
0.013

0.990



64
0.834
0.841
2.41

1.21

0.87


0.013



65
0.841
0.847

1.35

0.67

0.49
0.013

0.992



66
0.847
0.854
2.41

1.21

0.87


0.013



67
0.854
0.860

1.35

0.67

0.49
0.013

0.994



68
0.860
0.867
2.41

1.21

0.87


0.013



69
0.867
0.873

1.35

0.67

0.49
0.013

0.995



70
0.873
0.881
2.41

1.21

0.87


0.020



71
0.881
0.887
2.41

1.21

0.87



72
0.887
0.893

1.35

0.67

0.49
0.020

0.990



73
0.893
0.900
2.41

1.21

0.87


0.012



74
0.900
0.906

1.35

0.67

0.49
0.012

0.995



75
0.906
0.912
2.41

1.21

0.87


0.012



76
0.912
0.918

1.35

0.67

0.49
0.012

0.991



77
0.918
0.924
2.41

1.21

0.87


0.012



78
0.924
0.930

1.35

0.67

0.49
0.012

0.990



79
0.930
0.936
2.41

1.21

0.87


0.012



80
0.936
0.942

1.35

0.67

0.49
0.012

0.993



81
0.942
0.949
2.41

1.21

0.87


0.019



82
0.949
0.955
2.41

1.21

0.87



83
0.955
0.960

1.35

0.67

0.49
0.019

0.993



84
0.960
0.966
2.41

1.21

0.87


0.011



85
0.966
0.972

1.35

0.67

0.49
0.011

0.996



86
0.972
0.977
2.41

1.21

0.87


0.011



87
0.977
0.983

1.35

0.67

0.49
0.011

0.995



88
0.983
0.990
2.41

1.21

0.87


0.018



89
0.990
0.995
2.41

1.21

0.87



90
0.995
1.001

1.35

0.67

0.49
0.018

0.994



91
1.001
1.006
2.41

1.21

0.87


0.011



92
1.006
1.011

1.35

0.67

0.49
0.011

0.991



93
1.011
1.018
2.41

1.21

0.87


0.017



94
1.018
1.023
2.41

1.21

0.87



95
1.023
1.029

1.35

0.67

0.49
0.017

1.011



96
1.029
1.034
2.41

1.21

0.87


0.011



97
1.034
1.039

1.35

0.67

0.49
0.010

0.967



98
1.039
1.045
2.41

1.21

0.87


0.017



99
1.045
1.051
2.41

1.21

0.87



100
1.051
1.056

1.35

0.67

0.49
0.017

0.995



101
1.056
1.061
2.41

1.21

0.87


0.010



102
1.061
1.066

1.35

0.67

0.49
0.010

0.997



103
1.066
1.072
2.41

1.21

0.87


0.016



104
1.072
1.077
2.41

1.21

0.87



105
1.077
1.082

1.35

0.67

0.49
0.016

0.992



106
1.082
1.088
2.41

1.21

0.87


0.016



107
1.088
1.093
2.41

1.21

0.87



108
1.093
1.098

1.35

0.67

0.49
0.016

0.999



109
1.098
1.104
2.19

1.10

0.89


0.011



110
1.104
1.109

1.43

0.72

0.59
0.011

1.041


Second Area
111
1.109
1.115
2.19

1.10

0.89


0.011



112
1.115
1.120

1.43

0.72

0.59
0.010

0.968



113
1.120
1.125
2.19

1.10

0.89


0.013



114
1.125
1.127

1.43

0.72

0.59
0.012

0.990



115
1.127
1.132

1.43

0.72

0.59



116
1.132
1.137
2.19

1.10

0.89


0.010



117
1.137
1.142

1.43

0.72

0.59
0.010

0.990



118
1.142
1.147
2.19

1.10

0.89


0.012



119
1.147
1.149

1.43

0.72

0.59
0.012

0.989



120
1.149
1.154

1.43

0.72

0.59




























TABLE 54C







Second Area
121
1.154
1.158
2.19

1.10

0.89


0.009




122
1.158
1.163

1.43

0.72

0.59
0.009

0.990



123
1.163
1.167
2.19

1.10

0.89


0.009



124
1.167
1.172

1.43

0.72

0.59
0.009

0.990



125
1.172
1.176
2.19

1.10

0.89


0.009



126
1.176
1.181

1.43

0.72

0.59
0.009

0.989



127
1.181
1.185
2.19

1.10

0.89


0.009



128
1.185
1.190

1.43

0.72

0.59
0.009

0.990



129
1.190
1.194
2.19

1.10

0.89


0.009



130
1.194
1.198

1.43

0.72

0.59
0.009

0.989



131
1.198
1.202
2.19

1.10

0.89


0.008



132
1.202
1.206

1.43

0.72

0.59
0.008

0.989



133
1.206
1.211
2.19

1.10

0.89


0.008



134
1.211
1.215

1.43

0.72

0.59
0.008

0.989



135
1.215
1.221
2.19

1.10

0.89


0.014



136
1.221
1.224
2.19

1.10

0.89



137
1.224
1.228

1.43

0.72

0.59
0.014

0.990



138
1.228
1.234
2.19

1.10

0.89


0.013



139
1.234
1.238
2.19

1.10

0.89



140
1.238
1.242

1.43

0.72

0.59
0.013

0.990



141
1.242
1.247
2.19

1.10

0.89


0.013



142
1.247
1.251
2.19

1.10

0.89



144
1.251
1.255

1.43

0.72

0.59
0.013

0.989



145
1.255
1.260
2.19

1.10

0.89


0.018



146
1.260
1.265
2.19

1.10

0.89



147
1.265
1.269
2.19

1.10

0.89



148
1.269
1.272

1.43

0.72

0.59
0.018

0.990



149
1.272
1.277
2.19

1.10

0.89



150
1.277
1.282
2.19

1.10

0.89



151
1.282
1.287
2.19

1.10

0.89



152
1.287
1.292
2.19

1.10

0.89



153
1.292
1.297
2.19

1.10

0.89



154
1.297
1.301
2.19

1.10

0.89



155
1.301
1.306
2.19

1.10

0.89



156
1.306
1.310
2.19

1.10

0.89


Third Area
157
1.310
1.353
4.00

2.00

0.89



158
1.353
1.387
4.00

2.00

0.86



159
1.387
1.411
4.00

2.00

0.86



160
1.411
1.430
4.00

2.00

0.86



161
1.430
1.445
4.00

2.00

0.86



162
1.445
1.458
4.00

2.00

0.86



163
1.458
1.469
4.00

2.00

0.86



164
1.469
1.480
4.00

2.00

0.86



165
1.480
1.489
4.00

2.00

0.86



166
1.489
1.500
4.00

2.00

0.86









Tenth Example
Hereafter, a tenth example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the tenth example are shown in Tables 55 to 59 and 60A to 60C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the tenth example are shown in FIGS. 15A to 15C, respectively.












TABLE 55








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.764
2.000
2.064


NA

0.85
0.60
0.47


Magnification

0.00
0.00
0.00





















TABLE 56







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.114
1.880


Objective Lens


1-2
1.129


1-3
1.007


2
−2.935
0.672
0.625
0.319


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 57






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
2.81800E−02
−5.93400E−02 
−7.43130E−02
 3.77280E−01


A6
1.47400E−02
1.91700E−01
 8.02730E−02
−6.19460E−01


A8
−2.68700E−03 
−9.45800E−02 
−2.09870E−02
 9.56070E−01


A10
5.72900E−04
1.16600E−02
 1.92360E−02
−1.08940E+00


A12
−8.33800E−07 
5.08200E−04
−1.66450E−02
 8.30880E−01


A14


 7.39140E−03
−3.94180E−01


A16


−1.32860E−03
 1.04850E−01


A18



−1.18530E−02


A20


A22


A24



















TABLE 58





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
5.87700E+01
5.38870E+01
4.19810E+01


P4
−1.57240E+01 
−8.87100E+01 
−8.66560E+01 


P6
7.65100E+00
1.65500E+02
5.71620E+01


P8
−3.81500E+00 
−9.83500E+01 
−1.24450E+01 


P10
1.69900E−01
1.69850E+01
0.00000E+00


P12
0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 59







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−4.07780E+01
−4.41440E+01



P4
−7.35000E+00
−5.42840E+01



P6
 2.98700E+00
 1.06560E+02



P8
−2.86700E+00
−6.64150E+01



P10
 4.47400E−01
 1.21470E+01



P12
 0.00000E+00
 0.00000E+00





















TABLE 60A









Phase














Difference

Step Height
Annular Zone Pitch


















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
P1
P2





















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P3
P4
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
μm
μm
P3/P4























First Area
0
0.000
0.068












1
0.068
0.121

1.39

0.69

0.50



2
0.121
0.159
2.46

1.23

0.89


0.090



3
0.159
0.188

1.39

0.69

0.50
0.068

0.748



4
0.188
0.214
2.46

1.23

0.89


0.076



5
0.214
0.234

1.39

0.69

0.50
0.067

0.882



6
0.234
0.255

1.39

0.69

0.50



7
0.255
0.275
2.46

1.23

0.89


0.041



8
0.275
0.293

1.39

0.69

0.50
0.038

0.938



9
0.293
0.310
2.46

1.23

0.89


0.036



10
0.310
0.327

1.39

0.69

0.50
0.034

0.942



11
0.327
0.342
2.46

1.23

0.89


0.032



12
0.342
0.357

1.39

0.69

0.50
0.031

0.954



13
0.357
0.371
2.46

1.23

0.89


0.041



14
0.371
0.383

1.39

0.69

0.50
0.040

0.965



15
0.383
0.397

1.39

0.69

0.50



16
0.397
0.410
2.46

1.23

0.89


0.026



17
0.410
0.422

1.39

0.69

0.50
0.026

0.968



18
0.422
0.434
2.46

1.23

0.89


0.025



19
0.434
0.446

1.39

0.69

0.50
0.024

0.973



20
0.446
0.458
2.46

1.23

0.89


0.023



21
0.458
0.469

1.39

0.69

0.50
0.023

0.977



22
0.469
0.480
2.46

1.23

0.89


0.032



23
0.480
0.490

1.39

0.69

0.50
0.031

0.976



24
0.490
0.500

1.39

0.69

0.50



25
0.500
0.511
2.46

1.23

0.89


0.021



26
0.511
0.521

1.39

0.69

0.50
0.021

0.981



27
0.521
0.531
2.46

1.23

0.89


0.020



28
0.531
0.541

1.39

0.69

0.50
0.020

0.982



29
0.541
0.550
2.46

1.23

0.89


0.019



30
0.550
0.560

1.39

0.69

0.50
0.019

0.983



31
0.560
0.569
2.46

1.23

0.89


0.019



32
0.569
0.578

1.39

0.69

0.50
0.019

0.984



33
0.578
0.588
2.46

1.23

0.89


0.018



34
0.588
0.596

1.39

0.69

0.50
0.018

0.984



35
0.596
0.605
2.46

1.23

0.89


0.018



36
0.605
0.614

1.39

0.69

0.50
0.017

0.986



37
0.614
0.622
2.46

1.23

0.89


0.025



38
0.622
0.630

1.39

0.69

0.50
0.024

0.987



39
0.630
0.638

1.39

0.69

0.50



40
0.638
0.646
2.46

1.23

0.89


0.017



41
0.646
0.655

1.39

0.69

0.50
0.016

0.987



42
0.655
0.663
2.46

1.23

0.89


0.016



43
0.663
0.671

1.39

0.69

0.50
0.016

0.989



44
0.671
0.678
2.46

1.23

0.89


0.016



45
0.678
0.686

1.39

0.69

0.50
0.016

0.989



46
0.686
0.694
2.46

1.23

0.89


0.015



47
0.694
0.701

1.39

0.69

0.50
0.015

0.989



48
0.701
0.709
2.46

1.23

0.89


0.015



49
0.709
0.716

1.39

0.69

0.50
0.015

0.990



50
0.716
0.724
2.46

1.23

0.89


0.015



51
0.724
0.731

1.39

0.69

0.50
0.015

0.990



52
0.731
0.738
2.46

1.23

0.89


0.015



53
0.738
0.746

1.39

0.69

0.50
0.014

0.991



54
0.746
0.753
2.46

1.23

0.89


0.014



55
0.753
0.760

1.39

0.69

0.50
0.014

0.991



56
0.760
0.768
2.46

1.23

0.89


0.022



57
0.768
0.774
2.46

1.23

0.89



58
0.774
0.781

1.39

0.69

0.50
0.022

0.991



59
0.781
0.788
2.46

1.23

0.89


0.014



60
0.788
0.795

1.39

0.69

0.50
0.014

0.991




























TABLE 60B







First Area
61
0.795
0.801
2.46

1.23

0.89


0.013




62
0.801
0.808

1.39

0.69

0.50
0.013

0.992



63
0.808
0.815
2.46

1.23

0.89


0.013



64
0.815
0.821

1.39

0.69

0.50
0.013

0.992



65
0.821
0.828
2.46

1.23

0.89


0.013



66
0.828
0.834

1.39

0.69

0.50
0.013

0.992



67
0.834
0.840
2.46

1.23

0.89


0.013



68
0.840
0.847

1.39

0.69

0.50
0.013

0.992



69
0.847
0.853
2.46

1.23

0.89


0.013



70
0.853
0.859

1.39

0.69

0.50
0.012

0.993



71
0.859
0.866
2.46

1.23

0.89


0.019



72
0.866
0.872
2.46

1.23

0.89



73
0.872
0.878

1.39

0.69

0.50
0.019

0.993



74
0.878
0.884
2.46

1.23

0.89


0.012



75
0.884
0.890

1.39

0.69

0.50
0.012

0.993



76
0.890
0.896
2.46

1.23

0.89


0.012



77
0.896
0.902

1.39

0.69

0.50
0.012

0.993



78
0.902
0.908
2.46

1.23

0.89


0.012



79
0.908
0.914

1.39

0.69

0.50
0.012

0.994



80
0.914
0.921
2.46

1.23

0.89


0.018



81
0.921
0.926
2.46

1.23

0.89



82
0.926
0.932

1.39

0.69

0.50
0.018

0.993



83
0.932
0.938
2.46

1.23

0.89


0.011



84
0.938
0.943

1.39

0.69

0.50
0.011

0.993



85
0.943
0.949
2.46

1.23

0.89


0.011



86
0.949
0.955

1.39

0.69

0.50
0.011

0.993



87
0.955
0.961
2.46

1.23

0.89


0.021



88
0.961
0.966
2.46

1.23

0.89



89
0.966
0.970

1.39

0.69

0.50
0.021

1.021


Second Area
90
0.970
0.976

1.39

0.69

0.54



91
0.976
0.981
2.46

1.23

0.96


0.015



92
0.981
0.985

1.39

0.69

0.54
0.015

0.943



93
0.985
0.991

1.39

0.69

0.54



94
0.991
0.996
2.46

1.23

0.96


0.015



95
0.996
1.000

1.39

0.69

0.54
0.015

0.994



96
1.000
1.005

1.39

0.69

0.54



97
1.005
1.010
2.46

1.23

0.96


0.014



98
1.010
1.014

1.39

0.69

0.54
0.014

0.995



99
1.014
1.019

1.39

0.69

0.54



100
1.019
1.024
2.46

1.23

0.96


0.010



101
1.024
1.029

1.39

0.69

0.54
0.010

0.995



102
1.029
1.034
2.46

1.23

0.96


0.014



103
1.034
1.038

1.39

0.69

0.54
0.014

0.995



104
1.038
1.043

1.39

0.69

0.54



105
1.043
1.048
2.46

1.23

0.96


0.010



106
1.048
1.053

1.39

0.69

0.54
0.010

0.996



107
1.053
1.058
2.46

1.23

0.96


0.014



108
1.058
1.062

1.39

0.69

0.54
0.014

0.996



109
1.062
1.066

1.39

0.69

0.54



110
1.066
1.071
2.46

1.23

0.96


0.009



111
1.071
1.076

1.39

0.69

0.54
0.009

0.996



112
1.076
1.081
2.46

1.23

0.96


0.009



113
1.081
1.085

1.39

0.69

0.54
0.009

0.996



114
1.085
1.090
2.46

1.23

0.96


0.009



115
1.090
1.094

1.39

0.69

0.54
0.009

0.996



116
1.094
1.099
2.46

1.23

0.96


0.009



117
1.099
1.104

1.39

0.69

0.54
0.009

0.996



118
1.104
1.108
2.46

1.23

0.96


0.009



119
1.108
1.113

1.39

0.69

0.54
0.009

0.997



120
1.113
1.117
2.46

1.23

0.96


0.009




























TABLE 60C







Second Area
121
1.117
1.122

1.39

0.69

0.54
0.009

0.997



122
1.122
1.127
2.46

1.23

0.96


0.009



123
1.127
1.131

1.39

0.69

0.54
0.009

0.997



124
1.131
1.136
2.46

1.23

0.96


0.009



125
1.136
1.140

1.39

0.69

0.54
0.009

0.997



126
1.140
1.145
2.46

1.23

0.96


0.009



127
1.145
1.149

1.39

0.69

0.54
0.009

0.997



128
1.149
1.154
2.46

1.23

0.96


0.014



129
1.154
1.159
2.46

1.23

0.96



130
1.159
1.163

1.39

0.69

0.54
0.014

0.998



131
1.163
1.168
2.46

1.23

0.96


0.014



132
1.168
1.172
2.46

1.23

0.96



133
1.172
1.177

1.39

0.69

0.54
0.014

0.998



134
1.177
1.182
2.46

1.23

0.96


0.014



135
1.182
1.186
2.46

1.23

0.96



136
1.186
1.191

1.39

0.69

0.54
0.014

0.998



137
1.191
1.196
2.46

1.23

0.96



138
1.196
1.200
2.46

1.23

0.96


Third Area
139
1.200
1.344
4.00

2.00

0.83



140
1.344
1.389
4.00

2.00

0.83



141
1.389
1.415
4.00

2.00

0.83



142
1.415
1.433
4.00

2.00

0.83



144
1.433
1.447
4.00

2.00

0.83



145
1.447
1.459
4.00

2.00

0.83



146
1.459
1.470
4.00

2.00

0.83



147
1.470
1.480
4.00

2.00

0.83



148
1.480
1.488
4.00

2.00

0.83



149
1.488
1.500
4.00

2.00

0.83









Eleventh Example
Hereafter, an eleventh example of the objective lens 10 and the optical information recording/reproducing apparatus 100 is described. The specifications, numerical configurations defined when each of the optical discs OD1 to OD3 is used, coefficients for optical path difference functions, use diffraction orders, and configuration of the phase shift structure of the objective lens 10 according to the eleventh example are shown in Tables 55 to 59 and 60A to 60C. The wavefront aberrations caused when each of the optical discs OD1 to OD3 is used in the optical information recording/reproducing apparatus 100 according to the eleventh example are shown in FIGS. 16A to 16C, respectively.












TABLE 61








1st laser
2nd laser
3rd laser



unit
beam
beam
beam




















Design Wavelength
nm
405
660
790


Focal Length
mm
1.765
1.990
2.052


NA

0.85
0.65
0.53


Magnification

0.00
0.00
0.00





















TABLE 62







Surface







No.
r
d(405 nm)
d(660 nm)
d(790 nm)





1-1
1.110
1.880


Objective Lens


1-2
1.159


1-3
0.999


2
−2.938
0.673
0.613
0.304


3
∞
0.0875
0.600
1.200
Optical Disc


4
∞





Surface


No.
n(405 nm)
n(660 nm)
n(790 nm)





1-1
1.56023
1.54044
1.53653

Objective Lens


1-2


1-3


2


3
1.62231
1.57961
1.57307

Optical Disc


4




















TABLE 63






1-1
1-2
1-3
2


κ
−1.000
−1.000
−1.000
3.100







A4
2.87500E−02
−1.32030E−01 
−7.40620E−02
 3.77280E−01


A6
1.16900E−02
2.99630E−01
 7.84670E−02
−6.19460E−01


A8
−1.29800E−03 
−1.40280E−01 
−2.91270E−02
 9.56070E−01


A10
4.44600E−04
1.62390E−02
 3.18120E−02
−1.08940E+00


A12
7.32720E−06
1.74560E−03
−2.58000E−02
 8.30880E−01


A14


 1.08960E−02
−3.94180E−01


A16


−1.84820E−03
 1.04850E−01


A18



−1.18530E−02


A20


A22


A24



















TABLE 64





Diffraction
1-1
1-2
1-3


Order
1/1/1
1/1/—
2/—/—







P2
 5.76530E+01
4.20560E+01
8.96940E+01


P4
−1.40670E+01
−1.47290E+02 
−1.72020E+02 


P6
 4.99200E+00
2.64180E+02
1.07596E+02


P8
−2.65500E+00
−1.48720E+02 
−2.26400E+01 


P10
−6.08700E−02
2.61445E+01
0.00000E+00


P12
 0.00000E+00
0.00000E+00
0.00000E+00




















TABLE 65







Diffraction
1-1
1-2



Order
1/0/0
1/0/—









P2
−3.71940E+01
−4.79400E+01



P4
−7.44000E+00
−9.30210E+01



P6
 1.54700E+00
 1.71690E+02



P8
−8.66400E−01
−9.85410E+01



P10
−1.98200E−01
 1.76610E+01



P12
 0.00000E+00
 0.00000E+00





















TABLE 66A









Phase














Difference

Step Height
Annular Zone Pitch


















Annular Zone
Annular Zone
φ1
φ2
Optical Path Length
D1
D2
P1
P2





















Annular
Start Position
End Position
φ3
φ4
ΔOPD1/λ1
ΔOPD2/λ1
D3
D4
P3
P4
P1/P2



Zone No.
mm
mm
πrad
πrad
ΔOPD3/λ1
ΔOPD4/λ1
μm
μm
μm
μm
P3/P4























First Area
0
0.000
0.071












1
0.071
0.126

1.39

0.69

0.50



2
0.126
0.163
2.46

1.23

0.89


0.091



3
0.163
0.193

1.39

0.69

0.50
0.067

0.734



4
0.193
0.219
2.46

1.23

0.89


0.078



5
0.219
0.240

1.39

0.69

0.50
0.069

0.888



6
0.240
0.262

1.39

0.69

0.50



7
0.262
0.282
2.46

1.23

0.89


0.042



8
0.282
0.301

1.39

0.69

0.50
0.039

0.924



9
0.301
0.319
2.46

1.23

0.89


0.051



10
0.319
0.333

1.39

0.69

0.50
0.048

0.947



11
0.333
0.349

1.39

0.69

0.50



12
0.349
0.365
2.46

1.23

0.89


0.032



13
0.365
0.379

1.39

0.69

0.50
0.030

0.960



14
0.379
0.393
2.46

1.23

0.89


0.029



15
0.393
0.407

1.39

0.69

0.50
0.028

0.972



16
0.407
0.420
2.46

1.23

0.89


0.038



17
0.420
0.432

1.39

0.69

0.50
0.037

0.970



18
0.432
0.444

1.39

0.69

0.50



19
0.444
0.456
2.46

1.23

0.89


0.025



20
0.456
0.468

1.39

0.69

0.50
0.024

0.969



21
0.468
0.480
2.46

1.23

0.89


0.024



22
0.480
0.491

1.39

0.69

0.50
0.023

0.973



23
0.491
0.502
2.46

1.23

0.89


0.032



24
0.502
0.512

1.39

0.69

0.50
0.031

0.978



25
0.512
0.522

1.39

0.69

0.50



26
0.522
0.533
2.46

1.23

0.89


0.021



27
0.533
0.543

1.39

0.69

0.50
0.021

0.982



28
0.543
0.553
2.46

1.23

0.89


0.020



29
0.553
0.563

1.39

0.69

0.50
0.020

0.984



30
0.563
0.573
2.46

1.23

0.89


0.020



31
0.573
0.582

1.39

0.69

0.50
0.019

0.982



32
0.582
0.592
2.46

1.23

0.89


0.019



33
0.592
0.601

1.39

0.69

0.50
0.019

0.982



34
0.601
0.610
2.46

1.23

0.89


0.018



35
0.610
0.619

1.39

0.69

0.50
0.018

0.970



36
0.619
0.629
2.46

1.23

0.89


0.025



37
0.629
0.636

1.39

0.69

0.50
0.025

0.999



38
0.636
0.644

1.39

0.69

0.50



39
0.644
0.653
2.46

1.23

0.89


0.017



40
0.653
0.661

1.39

0.69

0.50
0.017

0.988



41
0.661
0.670
2.46

1.23

0.89


0.017



42
0.670
0.678

1.39

0.69

0.50
0.017

0.990



43
0.678
0.686
2.46

1.23

0.89


0.016



44
0.686
0.694

1.39

0.69

0.50
0.016

0.990



45
0.694
0.702
2.46

1.23

0.89


0.016



46
0.702
0.710

1.39

0.69

0.50
0.016

0.989



47
0.710
0.718
2.46

1.23

0.89


0.016



48
0.718
0.726

1.39

0.69

0.50
0.016

0.988



49
0.726
0.733
2.46

1.23

0.89


0.015



50
0.733
0.741

1.39

0.69

0.50
0.015

0.989



51
0.741
0.748
2.46

1.23

0.89


0.015



52
0.748
0.756

1.39

0.69

0.50
0.015

0.990



53
0.756
0.763
2.46

1.23

0.89


0.015



54
0.763
0.771

1.39

0.69

0.50
0.015

0.991



55
0.771
0.778
2.46

1.23

0.89


0.015



56
0.778
0.785

1.39

0.69

0.50
0.014

0.991



57
0.785
0.792
2.46

1.23

0.89


0.014



58
0.792
0.799

1.39

0.69

0.50
0.014

0.991



59
0.799
0.806
2.46

1.23

0.89


0.014



60
0.806
0.813

1.39

0.69

0.50
0.014

0.991




























TABLE 66B







First Area
61
0.813
0.820
2.46

1.23

0.89


0.014




62
0.820
0.827

1.39

0.69

0.50
0.014

0.992



63
0.827
0.833
2.46

1.23

0.89


0.014



64
0.833
0.840

1.39

0.69

0.50
0.013

0.994



65
0.840
0.848
2.46

1.23

0.89


0.021



66
0.848
0.854
2.46

1.23

0.89



67
0.854
0.861

1.39

0.69

0.50
0.021

1.009



68
0.861
0.867
2.46

1.23

0.89


0.013



69
0.867
0.874

1.39

0.69

0.50
0.013

0.969



70
0.874
0.880
2.46

1.23

0.89


0.013



71
0.880
0.887

1.39

0.69

0.50
0.013

0.993



72
0.887
0.893
2.46

1.23

0.89


0.013



73
0.893
0.899

1.39

0.69

0.50
0.013

0.992



74
0.899
0.906
2.46

1.23

0.89


0.013



75
0.906
0.912

1.39

0.69

0.50
0.012

0.992



76
0.912
0.919
2.46

1.23

0.89


0.019



77
0.919
0.925
2.46

1.23

0.89



78
0.925
0.931

1.39

0.69

0.50
0.019

0.994



79
0.931
0.937
2.46

1.23

0.89


0.012



80
0.937
0.943

1.39

0.69

0.50
0.012

0.995



81
0.943
0.949
2.46

1.23

0.89


0.012



82
0.949
0.955

1.39

0.69

0.50
0.012

0.996



83
0.955
0.962
2.46

1.23

0.89


0.019



84
0.962
0.968
2.46

1.23

0.89



85
0.968
0.973

1.39

0.69

0.50
0.018

0.994



86
0.973
0.979
2.46

1.23

0.89


0.012



87
0.979
0.985

1.39

0.69

0.50
0.012

0.992



88
0.985
0.992
2.46

1.23

0.89


0.018



89
0.992
0.997
2.46

1.23

0.89



90
0.997
1.003

1.39

0.69

0.50
0.018

0.996



91
1.003
1.009
2.46

1.23

0.89


0.011



92
1.009
1.014

1.39

0.69

0.50
0.011

0.997



93
1.014
1.021
2.46

1.23

0.89


0.018



94
1.021
1.026
2.46

1.23

0.89



95
1.026
1.032

1.39

0.69

0.50
0.017

0.993



96
1.032
1.037
2.46

1.23

0.89


0.011



97
1.037
1.043

1.39

0.69

0.50
0.011

0.994



98
1.043
1.049
2.46

1.23

0.89


0.017



99
1.049
1.054
2.46

1.23

0.89



100
1.054
1.060

1.39

0.69

0.50
0.017

0.998



101
1.060
1.066
2.46

1.23

0.89


0.017



102
1.066
1.071
2.46

1.23

0.89



103
1.071
1.077

1.39

0.69

0.50
0.017

0.993



104
1.077
1.084
2.46

1.23

0.89


0.023


Second Area
105
1.084
1.090
2.36

1.18

0.96



106
1.090
1.094

1.48

0.74

0.61
0.022

0.985



107
1.094
1.099

1.48

0.74

0.61



108
1.099
1.104
2.36

1.18

0.96


0.018



109
1.104
1.108

1.48

0.74

0.61
0.018

0.995



110
1.108
1.112

1.48

0.74

0.61



111
1.112
1.117

1.48

0.74

0.61



112
1.117
1.122
2.36

1.18

0.96


0.014



113
1.122
1.126

1.48

0.74

0.61
0.014

0.996



114
1.126
1.130

1.48

0.74

0.61



115
1.130
1.135
2.36

1.18

0.96


0.013



116
1.135
1.139

1.48

0.74

0.61
0.013

0.996



117
1.139
1.144

1.48

0.74

0.61



118
1.144
1.149
2.36

1.18

0.96


0.013



119
1.149
1.152

1.48

0.74

0.61
0.013

0.996



120
1.152
1.157

1.48

0.74

0.61




























TABLE 66C







Second Area
121
1.157
1.162
2.36

1.18

0.96


0.014




122
1.162
1.167

1.48

0.74

0.61
0.009

0.665



123
1.167
1.171
2.36

1.18

0.96


0.013



124
1.171
1.175

1.48

0.74

0.61
0.013

0.996



125
1.175
1.180

1.48

0.74

0.61



126
1.180
1.184
2.36

1.18

0.96


0.009



127
1.184
1.189

1.48

0.74

0.61
0.009

0.996



128
1.189
1.193
2.36

1.18

0.96


0.009



129
1.193
1.198

1.48

0.74

0.61
0.009

0.997



130
1.198
1.202
2.36

1.18

0.96


0.009



131
1.202
1.207

1.48

0.74

0.61
0.009

0.997



132
1.207
1.212
2.36

1.18

0.96


0.009



133
1.212
1.216

1.48

0.74

0.61
0.009

0.997



134
1.216
1.221
2.36

1.18

0.96


0.009



135
1.221
1.225

1.48

0.74

0.61
0.009

0.997



136
1.225
1.229
2.36

1.18

0.96


0.009



137
1.229
1.234

1.48

0.74

0.61
0.009

0.997



138
1.234
1.239
2.36

1.18

0.96


0.014



139
1.239
1.244
2.36

1.18

0.96



140
1.244
1.248

1.48

0.74

0.61
0.014

0.997



141
1.248
1.253
2.36

1.18

0.96


0.014



142
1.253
1.258
2.36

1.18

0.96



144
1.258
1.262

1.48

0.74

0.61
0.014

0.997



145
1.262
1.267
2.36

1.18

0.96


0.024



146
1.267
1.272
2.36

1.18

0.96



147
1.272
1.277
2.36

1.18

0.96



148
1.277
1.282
2.36

1.18

0.96



149
1.282
1.286

1.48

0.74

0.61
0.024

0.998



150
1.286
1.290
2.36

1.18

0.96


Third Area
151
1.290
1.321
2.00

1.00

0.87



152
1.321
1.354
2.00

1.00

0.87



153
1.354
1.376
2.00

1.00

0.87



154
1.376
1.393
2.00

1.00

0.87



155
1.393
1.406
2.00

1.00

0.87



156
1.406
1.418
2.00

1.00

0.87



157
1.418
1.428
2.00

1.00

0.87



158
1.428
1.437
2.00

1.00

0.87



159
1.437
1.445
2.00

1.00

0.87



160
1.445
1.452
2.00

1.00

0.87



161
1.452
1.459
2.00

1.00

0.87



162
1.459
1.465
2.00

1.00

0.87



163
1.465
1.471
2.00

1.00

0.87



164
1.471
1.476
2.00

1.00

0.87



165
1.476
1.481
2.00

1.00

0.87



166
1.481
1.486
2.00

1.00

0.87



167
1.486
1.491
2.00

1.00

0.87



168
1.491
1.495
2.00

1.00

0.87



169
1.495
1.500
2.00

1.00

0.87









Table 67 shows values calculated by applying the conditions (2) to (15) and (17) to (30) to the first to eleventh examples (regarding the arrangement intervals P1 to P4 of the conditions (1) and (16), see Tables showing the concrete configurations of the phase shift structures of each example). Table 68 shows a list of the light use efficiencies (diffraction efficiencies) defined when each of the optical discs OD1 to OD3 is used in the first to eleventh examples.


















TABLE 67









Lower
Lower
Upper
Upper










Limit
Limit
Limit
Limit
1st
2nd
3rd
4th
5th
6th



Unit
(1)
(2)
(2)
(1)
Example
Example
Example
Example
Example
Example





  φ1/   φ2

−3.00
−1.30
−0.35
−0.10
−0.757
−0.915
−0.727
−0.314
−0.693
−0.888


φ1
πrad
2.2
2.30
2.60
2.80
2.465
2.627
2.302
2.193
2.474
2.735


φ2
πrad
1.00
1.10
1.50
1.70
1.386
1.315
1.585
1.386
1.316
1.173


  OPD1/λ1

1.1
1.15
1.30
1.40
1.232
1.313
1.151
1.096
1.237
1.367


  OPD2/λ1

0.50
0.55
0.75
0.85
0.693
0.657
0.793
0.693
0.658
0.586


D1
μm
0.70
0.80
0.95
1.10
0.891
0.950
0.832
0.793
0.770
1.056


D2
μm
0.30
0.40
0.55
0.70
0.501
0.475
0.573
0.501
0.409
0.453


  φ3/   φ4

−2.70
−1.05
−0.20
−0.05
−0.685
−1.038
−0.686
−0.314
−0.952
−0.851


φ3
πrad
2.1
2.20
2.6
2.8
2.356
2.681
2.247
2.193
2.534
2.519


φ4
πrad
1.00
1.1
1.5
1.70
1.480
1.344
1.640
1.386
1.439
1.390


  OPD3/λ1

1.05
1.10
1.30
1.4
1.178
1.340
1.124
1.096
1.267
1.259


  OPD4/λ1

0.50
0.55
0.75
0.85
0.740
0.672
0.820
0.693
0.719
0.695


D3
μm
0.85
0.95
1.10
1.20
0.942
1.084
0.896
0.869
0.871
1.089


D4
μm
0.45
0.55
0.75
0.85
0.598
0.454
0.659
0.554
0.513
0.613






















Lower
Lower
Upper
Upper









Limit
Limit
Limit
Limit
7th
8th
9th
10th
11th



Unit
(1)
(2)
(2)
(1)
Example
Example
Example
Example
Example





  φ1/   φ2

−3.00
−1.30
−0.35
−0.10
−1.167
−0.912
−0.630
−0.757
−0.757


φ1
πrad
2.2
2.30
2.60
2.80
2.356
2.519
2.411
2.465
2.465


φ2
πrad
1.00
1.10
1.50
1.70
1.695
1.431
1.348
1.386
1.386


  OPD1/λ1

1.1
1.15
1.30
1.40
1.178
1.259
1.205
1.232
1.232


  OPD2/λ1

0.50
0.55
0.75
0.85
0.847
0.715
0.674
0.693
0.693


D1
μm
0.70
0.80
0.95
1.10
0.852
0.911
0.871
0.891
0.891


D2
μm
0.30
0.40
0.55
0.70
0.613
0.517
0.487
0.501
0.501


  φ3/   φ4

−2.70
−1.05
−0.20
−0.05
−0.685
−0.990
−0.338
−0.757
−0.685


φ3
πrad
2.1
2.20
2.6
2.8
2.465
2.411
2.193
2.465
2.356


φ4
πrad
1.00
1.1
1.5
1.70
1.322
1.585
1.431
1.386
1.480


  OPD3/λ1

1.05
1.10
1.30
1.4
1.232
1.205
1.096
1.232
1.178


  OPD4/λ1

0.50
0.55
0.75
0.85
0.661
0.793
0.715
0.693
0.740


D3
μm
0.85
0.95
1.10
1.20
0.852
1.014
0.888
0.958
0.960


D4
μm
0.45
0.55
0.75
0.85
0.517
0.675
0.585
0.543
0.610






















TABLE 68








1st
2nd
3rd
4th
5th
6th



Example
Example
Example
Example
Example
Example





Optical Disc OD1
82%
74%
91%
79%
76%
68%


Optical Disc OD2
61%
68%
57%
52%
67%
73%


Optical Disc OD3
62%
64%
50%
46%
79%
76%
















7th
8th
9th
10th
11th



Example
Example
Example
Example
Example





Optical Disc OD1
89%
82%
80%
82%
82%


Optical Disc OD2
50%
61%
63%
65%
63%


Optical Disc OD3
54%
63%
64%
60%
62%









As shown in Table 67, the objective lens 10 according to each of the first to eleventh examples satisfies at least the conditions (1) and (2). As a result, as shown in each of the wavefront aberration graphs of FIGS. 6A to 16C, phase changes which have substantially the same period and are in opposite directions are given to the laser beam having the wavelength λ1 passed through the first step and the laser beam having the wavelength λ1 passed through the second step, and these phase changes are cancelled with each other, thereby suppressing undulation of the wavefront. Therefore, the amount of the wavefront aberration is small. That is, the objective lens 10 according to each of the first to eleventh examples is able to suppress disturbance of the wavefront while giving the multiple optical effects by the first and second steps on the laser beams having the wavelengths λ1, λ2 and λ3. Therefore, as shown in Table 68, decrease of the light use efficiency due to the phase shift by the phase shift structure can be effectively suppressed. Furthermore, the objective lens 10 according to each of the first to eleventh examples is able to additionally provide the advantages achieved by additionally satisfying the conditions other than the conditions (1) and (2).
Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible.
This application claims priority of Japanese Patent Application No. P2011-156511, filed on Jul. 15, 2011. The entire subject matter of the application is incorporated herein by reference.

## Claims

1. An objective optical system for an optical information recording/reproducing apparatus configured to record information to and/or reproduce information from three types of optical discs including first, second and third optical discs differing in recording density, by selectively using light beams having first, second and third wavelengths emitted from light sources,
the objective optical system comprising at least an objective lens,
when λ1 (unit: nm) represents the first wavelength, λ2 (unit: nm) represents the second wavelength and λ3 (unit: nm) represents the third wavelength, λ1, λ2 and λ3 being defined as:


λ1≈405, λ2≈660, and λ3≈790,


when NA1 represents a numerical aperture required for the information recording or information reproducing for the first optical disc, NA2 represents a numerical aperture required for the information recording or information reproducing for the second optical disc, and NA3 represents a numerical aperture required for the information recording or information reproducing for the third optical disc, NA1, NA2 and NA3 satisfying a following relationship:


NA1>NA2>NA3,


at least one surface of the objective optical system being configured to be a phase shift surface having a phase shift structure including a plurality of refractive surface zones concentrically divided so as to have steps giving different phase differences to an incident light beam at a boundary between adjacent ones of the plurality of refractive surface zones,
wherein:
the phase shift surface has a first area contributing to converging the first, second and third light beams onto recording surfaces of the first, second and third optical discs, respectively;
the first area has an effective diameter larger than NA 0.3 at the first wavelength;
in the first area, the phase shift surface has at least two types of phase shift structures including a first phase shift structure having first steps and a second phase shift structure having second steps;
when P1 (unit: mm) represents an arrangement interval defined in a direction perpendicular to an optical axis direction between two first steps which adjoin with respect to each other while sandwiching at least one second step, and P2 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two second steps which adjoin with respect to each other while sandwiching at least one first step and one of which is sandwiched between the two first steps, the phase shift surface is configured such that, in an area whose effective diameter is larger than NA 0.3 at the first wavelength in the first area, the phase shift surface has a plurality of combinations of annular zones which satisfy a condition (1):


0.95<P1/P2<1.05  (1)

where,
one of the two first steps arranged closer to the optical axis is defines as a first start step, and the other of the two first steps farther from the optical axis is defined as a first end step,
when the first steps are continuously arranged in a direction perpendicular to the optical axis not to have the second steps therebetween, the arrangement interval P1 is determined by defining one of the continuously arranged first steps closest to the optical axis as the first start step and by defining the other of the continuously arranged first steps farthest from the optical axis as the first end step,
one of the two second steps arranged closer to the optical axis is defines as a second start step, and the other of the two second steps farther from the optical axis is defined as a second end step, and
when the second steps are continuously arranged in a direction perpendicular to the optical axis not to have the first steps therebetween, the arrangement interval P2 is determined by defining one of the continuously arranged second steps closest to the optical axis as the second start step and by defining the other of the continuously arranged second steps farthest from the optical axis as the second end step,

when Δφ1 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the first steps with respect to the light beam having the first wavelength in a case where the first steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ2 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the second steps with respect to the light beam having the first wavelength in a case where the second steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, in an area having an effective diameter larger than NA 0.3 at the first wavelength in the first area, the phase shift surface satisfies a following condition:


−3.00<Δφ1/Δφ2<−0.10  (2).

2. The objective optical system according to claim 1,
wherein the phase shift surface satisfies a following condition:


−1.30<Δφ1/Δφ2<−0.35  (3).

3. The objective optical system according to claim 1,
wherein, when φ1 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each first step and φ2 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each second step, the phase shift surface satisfies following conditions:


2.2<φ1<2.8  (4), and



1.0<φ2<1.70  (5).

4. The objective optical system according to claim 3,
wherein the phase shift surface satisfies following conditions:


2.3<φ1<2.6  (6), and



1.1<φ2<1.5  (7).

5. The objective optical system according to claim 1,
wherein, when ΔOPD1 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each first step, and ΔOPD2 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each second step, the phase shift surface satisfies following conditions:


1.1<ΔOPD1/λ1<1.4  (8), and



0.50<ΔOPD2/λ1<0.85  (9)

6. The objective optical system according to claim 5,
wherein the phase shift surface satisfies following conditions:


1.15<ΔOPD1/λ1<1.30  (10), and



0.55<ΔOPD2/λ1<0.75  (11).

7. The objective optical system according to claim 1,
wherein, when D1 (unit: μm) represents an absolute value of a height of the paraxially arranged first step in the optical axis direction, and D2 (unit: μm) represents an absolute value of the height of the paraxially arranged second step in the optical axis direction, the phase shift surface satisfies following conditions:


0.70<D1<1.10  (12), and



0.30<D2<0.70  (13).

8. The objective optical system according to claim 7,
wherein the phase shift surface satisfies following conditions:


0.80<D1<0.95  (14), and



0.40<D2<0.55  (15).

9. The objective optical system according to claim 1,
wherein:
when the at least two types of phase shift structures formed in the first area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:


φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ


where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik, represents a diffraction order at which the diffraction efficiency of an incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon),
the first phase shift structure is a diffraction structure defined by a first optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are all 1st orders; and
the second phase shift structure is a diffraction structure defined by a second optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are 1st order, 0-th order and 0-th order, respectively.

10. The objective optical system according to claim 1,
wherein:
the phase shift surface includes a second area which is located outside the first area and which contributes to converging the light beams having the first and second wavelengths onto recording surfaces of the first and second optical discs, respectively and does no contribute to converging the light beam having the third wavelength;
in the second area, the phase shift surface has at least two types of phase shift structures including a third phase shift structure having third steps and a fourth phase shift structure having fourth steps;
when P3 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two third steps which adjoin with respect to each other while sandwiching at least one fourth step, and P4 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two fourth steps which adjoin with respect to each other while sandwiching at least one third step and one of which is sandwiched between the two third steps, the phase shift surface satisfies a following condition:


0.95<P3/P4<1.05  (16);

where,
one of the two third steps arranged closer to the optical axis is defines as a third start step, and the other of the two third steps farther from the optical axis is defined as a third end step,
when the third steps are continuously arranged in a direction perpendicular to the optical axis not to have the fourth steps therebetween, the arrangement interval P3 is determined by defining one of the continuously arranged third steps closest to the optical axis as the third start step and by defining the other of the continuously arranged third steps farthest from the optical axis as the third end step,
one of the two fourth steps arranged closer to the optical axis is defines as a fourth start step, and the other of the two fourth steps farther from the optical axis is defined as a fourth end step, and
when the fourth steps are continuously arranged in a direction perpendicular to the optical axis not to have the third steps therebetween, the arrangement interval P4 is determined by defining one of the continuously arranged fourth steps closest to the optical axis as the fourth start step and by defining the other of the continuously arranged fourth steps farthest from the optical axis as the fourth end step,

when Δφ3 (unit: radian) is represents a difference between 2π and an absolute value of a phase change caused by the third steps with respect to the light beam having the first wavelength in a case where the third steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ4 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the fourth steps with respect to the light beam having the first wavelength in a case where the fourth steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, the phase shift surface satisfies a following condition:


−2.70<Δφ3/Δφ4<−0.05  (17).

11. The objective optical system according to claim 10,
wherein the phase shift surface satisfies a condition:


−1.05<Δφ3/Δφ4<−0.20  (18).

12. The objective optical system according to claim 10,
wherein, when φ3 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each third step and φ4 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each fourth step, the phase shift surface satisfies following conditions:


2.1<φ3<2.8  (19), and



1.0<φ4<1.70  (20).

13. The objective optical system according to claim 12,
wherein the phase shift surface satisfies following conditions:


2.2<φ3<2.6  (21), and



1.1<φ4<1.5  (22).

14. The objective optical system according to claim 10,
wherein, when ΔOPD3 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each third step, and ΔOPD4 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each fourth step, the phase shift surface satisfies following conditions:


1.05<ΔOPD3/λ1<1.4  (23), and



0.50<ΔOPD4/λ1<0.85  (24).

15. The objective optical system according to claim 14,
wherein the phase shift surface satisfies following conditions:


1.10<ΔOPD3/λ1<1.30  (25), and



0.55<ΔOPD4/λ1<0.75  (26).

16. The objective optical system according to claim 10,
wherein, when D3 (unit: mm) represents an absolute value of a height of the paraxially arranged third step in the optical axis direction, and D4 (unit: mm) represents an absolute value of a height of the paraxially arranged fourth step in the optical axis direction, the phase shift surface satisfies following conditions:


0.85<D3<1.20  (27), and



0.45<D4<0.85  (28).

17. The objective optical system according to claim 16,
wherein the phase shift surface satisfies following conditions:


0.95<D3<1.10  (29), and



0.55<D4<0.75  (30).

18. The objective optical system according to claim 10,
wherein:
when the at least two types of phase shift structures formed in the second area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:


φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ


where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik, represents a diffraction order at which the diffraction efficiency of the incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon),
the third phase shift structure is a diffraction structure defined by a third optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are all 1st orders; and
the fourth phase shift structure is a diffraction structure defined by a fourth optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are 1st order and 0-th order, respectively.

19. The objective optical system according to claim 10,
wherein the phase shift surface has a third area which is located outside the second area and which is configured to contribute to converging the light beams having the first wavelength onto the recording surface of the first optical disc and not to contribute converging the light beams having the second and third wavelengths.

20. An optical information recording/reproducing apparatus for recording information and/or reproducing information from three types of optical discs including first, second and third optical discs, comprising:
light sources that emit light beams having a first wave length, a second wavelength and a third wavelength;
coupling lenses respectively converting degrees of divergence or convergence of the light beams having the first, second and third wavelengths emitted by the light sources; and
an objective optical system that converges the light beams whose degrees of divergence or convergence have been converted, onto recording surfaces of the first, second and third optical discs, respectively,
wherein:
the objective optical system comprises at least an objective lens,
when λ1 (unit: nm) represents the first wavelength, λ2 (unit: nm) represents the second wavelength and λ3 (unit: nm) represents the third wavelength λ1, λ2 and λ3 being defined as:


λ1≈405, λ2≈660, and λ3≈790,


when NA1 represents a numerical aperture required for the information recording or information reproducing for the first optical disc, NA2 represents a numerical aperture required for the information recording or information reproducing for the second optical disc, and NA3 represents a numerical aperture required for the information recording or information reproducing for the third optical disc, NA1, NA2 and NA3 satisfy a following relationship:


NA1>NA2>NA3,


at least one surface of the objective optical system being configured to be a phase shift surface having a phase shift structure including a plurality of refractive surface zones concentrically divided so as to have steps giving different phase differences to an incident light beam at a boundary between adjacent ones of the plurality of refractive surface zones,
the phase shift surface has a first area contributing to converging the first, second and third light beams onto recording surfaces of the first, second and third optical discs, respectively;
the first area has an effective diameter larger than NA 0.3 at the first wavelength;
in the first area, the phase shift surface has at least two types of phase shift structures including a first phase shift structure having first steps and a second phase shift structure having second steps;
when P1 (unit: mm) represents an arrangement interval defined in a direction perpendicular to an optical axis direction between two first steps which adjoin with respect to each other while sandwiching at least one second step, and P2 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two second steps which adjoin with respect to each other while sandwiching at least one first step and one of which is sandwiched between the two first steps, the phase shift surface is configured such that, in an area whose effective diameter is larger than NA 0.3 at the first wavelength in the area R1, the phase shift surface has a plurality of combinations of annular zones which satisfy a condition (1):


0.95<P1/P2<1.05  (1)

where,
one of the two first steps arranged closer to the optical axis is defines as a first start step, and the other of the two first steps farther from the optical axis is defined as a first end step,
when the first steps are continuously arranged in a direction perpendicular to the optical axis not to have the second steps therebetween, the arrangement interval P1 is determined by defining one of the continuously arranged first steps closest to the optical axis as the first start step and by defining the other of the continuously arranged first steps farthest from the optical axis as the first end step,
one of the two second steps arranged closer to the optical axis is defines as a second start step, and the other of the two second steps farther from the optical axis is defined as a second end step, and
when the second steps are continuously arranged in a direction perpendicular to the optical axis not to have the first steps therebetween, the arrangement interval P2 is determined by defining one of the continuously arranged second steps closest to the optical axis as the second start step and by defining the other of the continuously arranged second steps farthest from the optical axis as the second end step,

when Δφ1 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the first steps with respect to the light beam having the first wavelength in a case where the first steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ2 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the second steps with respect to the light beam having the first wavelength in a case where the second steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, in an area having an effective diameter larger than NA 0.3 at the first wavelength in the first area, the phase shift surface satisfies a following condition:


−3.00<Δφ1/Δφ2<−0.10  (2).

21. The optical information recording/reproducing apparatus according to claim 20,
wherein the phase shift surface satisfies a following condition:


−1.30<Δφ1/Δφ2<−0.35  (3).

22. The optical information recording/reproducing apparatus according to claim 20,
wherein, when φ1 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each first step and φ2 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each second step, the phase shift surface satisfies following conditions:


2.2<φ1<2.8  (4), and



1.0<φ2<1.70  (5).

23. The optical information recording/reproducing apparatus according to claim 22,
wherein the phase shift surface satisfies following conditions:


2.3<φ1<2.6  (6), and



1.1<φ2<1.5  (7).

24. The optical information recording/reproducing apparatus according to claim 20,
wherein, when ΔOPD1 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each first step, and ΔOPD2 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each second step, the phase shift surface satisfies following conditions:


1.1<ΔOPD1/λ1<1.4  (8), and



0.50<ΔOPD2/λ1<0.85  (9)

25. The optical information recording/reproducing apparatus according to claim 24,
wherein the phase shift surface satisfies following conditions:


1.15<ΔOPD1/λ1<1.30  (10), and



0.55<ΔOPD2/λ1<0.75  (11).

26. The optical information recording/reproducing apparatus according to claim 20,
wherein, when D1 (unit: μm) represents an absolute value of a height of the paraxially arranged first step in the optical axis direction, and D2 (unit: μm) represents an absolute value of the height of the paraxially arranged second step in the optical axis direction, the phase shift surface satisfies following conditions:


0.70<D1<1.10  (12), and



0.30<D2<0.70  (13).

27. The optical information recording/reproducing apparatus according to claim 26,
wherein the phase shift surface satisfies following conditions:


0.80<D1<0.95  (14), and



0.40<D2<0.55  (15).

28. The optical information recording/reproducing apparatus according to claim 20,
wherein:
when the at least two types of phase shift structures formed in the first area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:


φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ


where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik represents a diffraction order at which the diffraction efficiency of an incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon),
the first phase shift structure is a diffraction structure defined by a first optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are all 1st orders; and
the second phase shift structure is a diffraction structure defined by a second optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first, second and third wavelengths are maximized are 1st order, 0-th order and 0-th order, respectively.

29. The optical information recording/reproducing apparatus according to claim 20,
wherein:
the phase shift surface includes a second area which is located outside the first area and which contributes to converging the light beams having the first and second wavelengths onto recording surfaces of the first and second optical discs, respectively and does no contribute to converging the light beam having the third wavelength;
in the second area, the phase shift surface has at least two types of phase shift structures including a third phase shift structure having third steps and a fourth phase shift structure having fourth steps;
when P3 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two third steps which adjoin with respect to each other while sandwiching at least one fourth step, and P4 (unit: mm) represents an arrangement interval defined in a direction perpendicular to the optical axis direction between two fourth steps which adjoin with respect to each other while sandwiching at least one third step and one of which is sandwiched between the two third steps, the phase shift surface satisfies a following condition:


0.95<P3/P4<1.05  (16);

where,
one of the two third steps arranged closer to the optical axis is defines as a third start step, and the other of the two third steps farther from the optical axis is defined as a third end step,
when the third steps are continuously arranged in a direction perpendicular to the optical axis not to have the fourth steps therebetween, the arrangement interval P3 is determined by defining one of the continuously arranged third steps closest to the optical axis as the third start step and by defining the other of the continuously arranged third steps farthest from the optical axis as the third end step,
one of the two fourth steps arranged closer to the optical axis is defines as a fourth start step, and the other of the two fourth steps farther from the optical axis is defined as a fourth end step, and
when the fourth steps are continuously arranged in a direction perpendicular to the optical axis not to have the third steps therebetween, the arrangement interval P4 is determined by defining one of the continuously arranged fourth steps closest to the optical axis as the fourth start step and by defining the other of the continuously arranged fourth steps farthest from the optical axis as the fourth end step,

when Δφ3 (unit: radian) is represents a difference between 2π and an absolute value of a phase change caused by the third steps with respect to the light beam having the first wavelength in a case where the third steps give an additional optical path length to the light beam having the first wavelength in a direction proceeding along the optical axis from each light source to an optical disc being used, and Δφ4 (unit: radian) represents a difference between 2π and an absolute value of a phase change caused by the fourth steps with respect to the light beam having the first wavelength in a case where the fourth steps give an additional optical path length to the light beam having the first wavelength in a direction opposite to the direction proceeding along the optical axis from the light source to the optical disc being used, the phase shift surface satisfies a following condition:


−2.70<Δφ3/Δφ4<−0.05  (17).

30. The optical information recording/reproducing apparatus according to claim 29,
wherein the phase shift surface satisfies a condition:


−1.05<Δφ3/Δφ4<−0.20  (18).

31. The optical information recording/reproducing apparatus according to claim 29,
wherein, when φ3 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each third step and φ4 (unit: πradian) represents an absolute value of a phase difference given to the light beam having the first wavelength by each fourth step, the phase shift surface satisfies following conditions:


2.1<φ3<2.8  (19), and



1.0<φ4<1.70  (20).

32. The optical information recording/reproducing apparatus according to claim 31,
wherein the phase shift surface satisfies following conditions:


2.2<φ3<2.6  (21), and



1.1<φ4<1.5  (22).

33. The optical information recording/reproducing apparatus according to claim 29,
wherein, when ΔOPD3 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each third step, and ΔOPD4 (unit: μm) represents an absolute value of an optical path length difference given to the light beam having the first wavelength by each fourth step, the phase shift surface satisfies following conditions:


1.05<ΔOPD3/λ1<1.4  (23), and



0.50<ΔOPD4/λ1<0.85  (24).

34. The optical information recording/reproducing apparatus according to claim 33,
wherein the phase shift surface satisfies following conditions:


1.10<ΔOPD3/λ1<1.30  (25), and



0.55<ΔOPD4/λ1<0.75  (26).

35. The optical information recording/reproducing apparatus according to claim 29,
wherein, when D3 (unit: mm) represents an absolute value of a height of the paraxially arranged third step in the optical axis direction, and D4 (unit: mm) represents an absolute value of a height of the paraxially arranged fourth step in the optical axis direction, the phase shift surface satisfies following conditions:


0.85<D3<1.20  (27), and



0.45<D4<0.85  (28).

36. The optical information recording/reproducing apparatus according to claim 35,
wherein the phase shift surface satisfies following conditions:


0.95<D3<1.10  (29), and



0.55<D4<0.75  (30).

37. The optical information recording/reproducing apparatus according to claim 29,
wherein:
when the at least two types of phase shift structures formed in the second area are expressed by diffraction structures defined by expanding an optical path difference function in a form of a following equation:


φik(h)=(Pik2×h2+Pik4×h4+Pik6×h6+Pik8×h8+Pik10×h10+Pik12×h12)mikλ


where Pik2, Pik4, Pik6 . . . represent coefficients of the 2nd order, 4th order, 6th order, h represents a height from the optical axis, mik represents a diffraction order at which the diffraction efficiency of the incident light beam is maximized for the i-th optical path difference function in the k-th area, and λ represents a design wavelength of the light beam being used (incident thereon),
the third phase shift structure is a diffraction structure defined by a third optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are all 1st orders; and
the fourth phase shift structure is a diffraction structure defined by a fourth optical path difference function in which diffraction orders at which diffraction efficiencies for the light beams having the first and second wavelengths are maximized are 1 order and 0-th order, respectively.

38. The optical information recording/reproducing apparatus according to claim 29,
wherein the phase shift surface has a third area which is located outside the second area and which is configured to contribute to converging the light beams having the first wavelength onto the recording surface of the first optical disc and not to contribute converging the light beams having the second and third wavelengths.